Merge remote-tracking branch 'upstream/master'

24 files changed, 427 insertions, 1580 deletions

diff --git a/src/System.IO.FileSystem/src/PinvokeAnalyzerExceptionList.analyzerdata b/src/System.IO.FileSystem/src/PinvokeAnalyzerExceptionList.analyzerdata
deleted file mode 100644
index 4b690b7504..0000000000
--- a/src/System.IO.FileSystem/src/PinvokeAnalyzerExceptionList.analyzerdata
+++ /dev/null
@@ -1,6 +0,0 @@
-kernel32.dll!CopyFileExW
-kernel32.dll!CreateFileW
-kernel32.dll!DeleteVolumeMountPointW
-kernel32.dll!GetLogicalDrives
-kernel32.dll!SetThreadErrorMode
-
diff --git a/src/System.IO.FileSystem/src/System.IO.FileSystem.csproj b/src/System.IO.FileSystem/src/System.IO.FileSystem.csproj
index 1036cfbf78..c604f2f0af 100644
--- a/src/System.IO.FileSystem/src/System.IO.FileSystem.csproj
+++ b/src/System.IO.FileSystem/src/System.IO.FileSystem.csproj
@@ -63,6 +63,7 @@
   </ItemGroup>
   <!-- Windows -->
   <ItemGroup Condition="'$(TargetsWindows)' == 'true'">
+    <Compile Include="System\IO\DisableMediaInsertionPrompt.cs" />
     <Compile Include="Microsoft\Win32\SafeHandles\SafeFindHandle.Windows.cs" />
     <Compile Include="System\IO\DirectoryInfo.Windows.cs" />
     <Compile Include="System\IO\FileInfo.Windows.cs" />
@@ -235,9 +236,7 @@
     <Compile Include="System\IO\FileSystemInfo.WinRT.cs" />
     <Compile Include="System\IO\MultiplexingWin32WinRTFileSystem.cs" />
     <Compile Include="System\IO\WinRTIOExtensions.cs" />
-    <Compile Include="System\IO\WinRTFileStream.cs" />
     <Compile Include="System\IO\WinRTFileSystem.cs" />
-    <Compile Include="System\IO\WinRTFileSystemObject.cs" />
     <Compile Include="$(CommonPath)\Interop\Windows\kernel32\Interop.CopyFile2.cs">
       <Link>Common\Interop\Windows\Interop.CopyFile2.cs</Link>
     </Compile>
diff --git a/src/System.IO.FileSystem/src/System/IO/Directory.cs b/src/System.IO.FileSystem/src/System/IO/Directory.cs
index cd7ada9dd2..8039cc6a83 100644
--- a/src/System.IO.FileSystem/src/System/IO/Directory.cs
+++ b/src/System.IO.FileSystem/src/System/IO/Directory.cs
@@ -2,25 +2,16 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
-using System.Collections;
 using System.Collections.Generic;
-using System.Security;
-using Microsoft.Win32;
-using Microsoft.Win32.SafeHandles;
-using System.Text;
-using System.Runtime.InteropServices;
-using System.Globalization;
-using System.Runtime.Versioning;
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
-using System.Threading;
+using System.Security;
 
 namespace System.IO
 {
     public static partial class Directory
     {
-        public static DirectoryInfo GetParent(String path)
+        public static DirectoryInfo GetParent(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -29,16 +20,16 @@ namespace System.IO
                 throw new ArgumentException(SR.Argument_PathEmpty, nameof(path));
             Contract.EndContractBlock();
 
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
 
-            String s = Path.GetDirectoryName(fullPath);
+            string s = Path.GetDirectoryName(fullPath);
             if (s == null)
                 return null;
             return new DirectoryInfo(s);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static DirectoryInfo CreateDirectory(String path)
+        public static DirectoryInfo CreateDirectory(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -46,7 +37,7 @@ namespace System.IO
                 throw new ArgumentException(SR.Argument_PathEmpty, nameof(path));
             Contract.EndContractBlock();
 
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
 
             FileSystem.Current.CreateDirectory(fullPath);
 
@@ -55,9 +46,9 @@ namespace System.IO
 
         // Input to this method should already be fullpath. This method will ensure that we append 
         // the trailing slash only when appropriate.
-        internal static String EnsureTrailingDirectorySeparator(string fullPath)
+        internal static string EnsureTrailingDirectorySeparator(string fullPath)
         {
-            String fullPathWithTrailingDirectorySeparator;
+            string fullPathWithTrailingDirectorySeparator;
 
             if (!PathHelpers.EndsInDirectorySeparator(fullPath))
                 fullPathWithTrailingDirectorySeparator = fullPath + PathHelpers.DirectorySeparatorCharAsString;
@@ -74,7 +65,7 @@ namespace System.IO
         // contents.
         //
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static bool Exists(String path)
+        public static bool Exists(string path)
         {
             try
             {
@@ -83,7 +74,7 @@ namespace System.IO
                 if (path.Length == 0)
                     return false;
 
-                String fullPath = Path.GetFullPath(path);
+                string fullPath = Path.GetFullPath(path);
 
                 return FileSystem.Current.DirectoryExists(fullPath);
             }
@@ -96,78 +87,78 @@ namespace System.IO
             return false;
         }
 
-        public static void SetCreationTime(String path, DateTime creationTime)
+        public static void SetCreationTime(string path, DateTime creationTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetCreationTime(fullPath, creationTime, asDirectory: true);
         }
 
-        public static void SetCreationTimeUtc(String path, DateTime creationTimeUtc)
+        public static void SetCreationTimeUtc(string path, DateTime creationTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetCreationTime(fullPath, File.GetUtcDateTimeOffset(creationTimeUtc), asDirectory: true);
         }
 
-        public static DateTime GetCreationTime(String path)
+        public static DateTime GetCreationTime(string path)
         {
             return File.GetCreationTime(path);
         }
 
-        public static DateTime GetCreationTimeUtc(String path)
+        public static DateTime GetCreationTimeUtc(string path)
         {
             return File.GetCreationTimeUtc(path);
         }
  
-        public static void SetLastWriteTime(String path, DateTime lastWriteTime)
+        public static void SetLastWriteTime(string path, DateTime lastWriteTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastWriteTime(fullPath, lastWriteTime, asDirectory: true);
         }
 
-        public static void SetLastWriteTimeUtc(String path, DateTime lastWriteTimeUtc)
+        public static void SetLastWriteTimeUtc(string path, DateTime lastWriteTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastWriteTime(fullPath, File.GetUtcDateTimeOffset(lastWriteTimeUtc), asDirectory: true);
         }
 
-        public static DateTime GetLastWriteTime(String path)
+        public static DateTime GetLastWriteTime(string path)
         {
             return File.GetLastWriteTime(path);
         }
 
-        public static DateTime GetLastWriteTimeUtc(String path)
+        public static DateTime GetLastWriteTimeUtc(string path)
         {
             return File.GetLastWriteTimeUtc(path);
         }
 
-        public static void SetLastAccessTime(String path, DateTime lastAccessTime)
+        public static void SetLastAccessTime(string path, DateTime lastAccessTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastAccessTime(fullPath, lastAccessTime, asDirectory: true);
         }
 
-        public static void SetLastAccessTimeUtc(String path, DateTime lastAccessTimeUtc)
+        public static void SetLastAccessTimeUtc(string path, DateTime lastAccessTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastAccessTime(fullPath, File.GetUtcDateTimeOffset(lastAccessTimeUtc), asDirectory: true);
         }
 
-        public static DateTime GetLastAccessTime(String path)
+        public static DateTime GetLastAccessTime(string path)
         {
             return File.GetLastAccessTime(path);
         }
 
-        public static DateTime GetLastAccessTimeUtc(String path)
+        public static DateTime GetLastAccessTimeUtc(string path)
         {
             return File.GetLastAccessTimeUtc(path);
         }
 
         // Returns an array of filenames in the DirectoryInfo specified by path
-        public static String[] GetFiles(String path)
+        public static string[] GetFiles(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFiles(path, "*", SearchOption.TopDirectoryOnly);
@@ -175,13 +166,13 @@ namespace System.IO
 
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search pattern (i.e. "*.txt").
-        public static String[] GetFiles(String path, String searchPattern)
+        public static string[] GetFiles(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFiles(path, searchPattern, SearchOption.TopDirectoryOnly);
@@ -189,7 +180,7 @@ namespace System.IO
 
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search pattern (i.e. "*.txt") and search option
-        public static String[] GetFiles(String path, String searchPattern, SearchOption searchOption)
+        public static string[] GetFiles(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -197,7 +188,7 @@ namespace System.IO
                 throw new ArgumentNullException(nameof(searchPattern));
             if ((searchOption != SearchOption.TopDirectoryOnly) && (searchOption != SearchOption.AllDirectories))
                 throw new ArgumentOutOfRangeException(nameof(searchOption), SR.ArgumentOutOfRange_Enum);
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFiles(path, searchPattern, searchOption);
@@ -205,7 +196,7 @@ namespace System.IO
 
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search pattern (i.e. "*.txt") and search option
-        private static String[] InternalGetFiles(String path, String searchPattern, SearchOption searchOption)
+        private static string[] InternalGetFiles(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
@@ -215,11 +206,11 @@ namespace System.IO
         }
 
         // Returns an array of Directories in the current directory.
-        public static String[] GetDirectories(String path)
+        public static string[] GetDirectories(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetDirectories(path, "*", SearchOption.TopDirectoryOnly);
@@ -227,13 +218,13 @@ namespace System.IO
 
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
-        public static String[] GetDirectories(String path, String searchPattern)
+        public static string[] GetDirectories(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetDirectories(path, searchPattern, SearchOption.TopDirectoryOnly);
@@ -241,7 +232,7 @@ namespace System.IO
 
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
-        public static String[] GetDirectories(String path, String searchPattern, SearchOption searchOption)
+        public static string[] GetDirectories(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -249,7 +240,7 @@ namespace System.IO
                 throw new ArgumentNullException(nameof(searchPattern));
             if ((searchOption != SearchOption.TopDirectoryOnly) && (searchOption != SearchOption.AllDirectories))
                 throw new ArgumentOutOfRangeException(nameof(searchOption), SR.ArgumentOutOfRange_Enum);
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetDirectories(path, searchPattern, searchOption);
@@ -257,22 +248,22 @@ namespace System.IO
 
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
-        private static String[] InternalGetDirectories(String path, String searchPattern, SearchOption searchOption)
+        private static string[] InternalGetDirectories(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
 
             return InternalGetFileDirectoryNames(path, path, searchPattern, false, true, searchOption);
         }
 
         // Returns an array of strongly typed FileSystemInfo entries in the path
-        public static String[] GetFileSystemEntries(String path)
+        public static string[] GetFileSystemEntries(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFileSystemEntries(path, "*", SearchOption.TopDirectoryOnly);
@@ -280,13 +271,13 @@ namespace System.IO
 
         // Returns an array of strongly typed FileSystemInfo entries in the path with the
         // given search criteria (i.e. "*.txt"). We disallow .. as a part of the search criteria
-        public static String[] GetFileSystemEntries(String path, String searchPattern)
+        public static string[] GetFileSystemEntries(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFileSystemEntries(path, searchPattern, SearchOption.TopDirectoryOnly);
@@ -294,7 +285,7 @@ namespace System.IO
 
         // Returns an array of strongly typed FileSystemInfo entries in the path with the
         // given search criteria (i.e. "*.txt"). We disallow .. as a part of the search criteria
-        public static String[] GetFileSystemEntries(String path, String searchPattern, SearchOption searchOption)
+        public static string[] GetFileSystemEntries(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -302,13 +293,13 @@ namespace System.IO
                 throw new ArgumentNullException(nameof(searchPattern));
             if ((searchOption != SearchOption.TopDirectoryOnly) && (searchOption != SearchOption.AllDirectories))
                 throw new ArgumentOutOfRangeException(nameof(searchOption), SR.ArgumentOutOfRange_Enum);
-            Contract.Ensures(Contract.Result<String[]>() != null);
+            Contract.Ensures(Contract.Result<string[]>() != null);
             Contract.EndContractBlock();
 
             return InternalGetFileSystemEntries(path, searchPattern, searchOption);
         }
 
-        private static String[] InternalGetFileSystemEntries(String path, String searchPattern, SearchOption searchOption)
+        private static string[] InternalGetFileSystemEntries(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
@@ -322,19 +313,19 @@ namespace System.IO
         // the given search criteria against every dir.
         // For all the dirs/files returned, it will then demand path discovery permission for 
         // their parent folders (it will avoid duplicate permission checks)
-        internal static String[] InternalGetFileDirectoryNames(String path, String userPathOriginal, String searchPattern, bool includeFiles, bool includeDirs, SearchOption searchOption)
+        internal static string[] InternalGetFileDirectoryNames(string path, string userPathOriginal, string searchPattern, bool includeFiles, bool includeDirs, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(userPathOriginal != null);
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
 
-            IEnumerable<String> enumerable = FileSystem.Current.EnumeratePaths(path, searchPattern, searchOption,
+            IEnumerable<string> enumerable = FileSystem.Current.EnumeratePaths(path, searchPattern, searchOption,
                 (includeFiles ? SearchTarget.Files : 0) | (includeDirs ? SearchTarget.Directories : 0));
             return EnumerableHelpers.ToArray(enumerable);
         }
 
-        public static IEnumerable<String> EnumerateDirectories(String path)
+        public static IEnumerable<string> EnumerateDirectories(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -343,7 +334,7 @@ namespace System.IO
             return InternalEnumerateDirectories(path, "*", SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateDirectories(String path, String searchPattern)
+        public static IEnumerable<string> EnumerateDirectories(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -354,7 +345,7 @@ namespace System.IO
             return InternalEnumerateDirectories(path, searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateDirectories(String path, String searchPattern, SearchOption searchOption)
+        public static IEnumerable<string> EnumerateDirectories(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -367,7 +358,7 @@ namespace System.IO
             return InternalEnumerateDirectories(path, searchPattern, searchOption);
         }
 
-        private static IEnumerable<String> InternalEnumerateDirectories(String path, String searchPattern, SearchOption searchOption)
+        private static IEnumerable<string> InternalEnumerateDirectories(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
@@ -376,29 +367,29 @@ namespace System.IO
             return EnumerateFileSystemNames(path, searchPattern, searchOption, false, true);
         }
 
-        public static IEnumerable<String> EnumerateFiles(String path)
+        public static IEnumerable<string> EnumerateFiles(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFiles(path, "*", SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateFiles(String path, String searchPattern)
+        public static IEnumerable<string> EnumerateFiles(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFiles(path, searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateFiles(String path, String searchPattern, SearchOption searchOption)
+        public static IEnumerable<string> EnumerateFiles(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -406,45 +397,45 @@ namespace System.IO
                 throw new ArgumentNullException(nameof(searchPattern));
             if ((searchOption != SearchOption.TopDirectoryOnly) && (searchOption != SearchOption.AllDirectories))
                 throw new ArgumentOutOfRangeException(nameof(searchOption), SR.ArgumentOutOfRange_Enum);
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFiles(path, searchPattern, searchOption);
         }
 
-        private static IEnumerable<String> InternalEnumerateFiles(String path, String searchPattern, SearchOption searchOption)
+        private static IEnumerable<string> InternalEnumerateFiles(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
 
             return EnumerateFileSystemNames(path, searchPattern, searchOption, true, false);
         }
 
-        public static IEnumerable<String> EnumerateFileSystemEntries(String path)
+        public static IEnumerable<string> EnumerateFileSystemEntries(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFileSystemEntries(path, "*", SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateFileSystemEntries(String path, String searchPattern)
+        public static IEnumerable<string> EnumerateFileSystemEntries(string path, string searchPattern)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFileSystemEntries(path, searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public static IEnumerable<String> EnumerateFileSystemEntries(String path, String searchPattern, SearchOption searchOption)
+        public static IEnumerable<string> EnumerateFileSystemEntries(string path, string searchPattern, SearchOption searchOption)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -452,48 +443,48 @@ namespace System.IO
                 throw new ArgumentNullException(nameof(searchPattern));
             if ((searchOption != SearchOption.TopDirectoryOnly) && (searchOption != SearchOption.AllDirectories))
                 throw new ArgumentOutOfRangeException(nameof(searchOption), SR.ArgumentOutOfRange_Enum);
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
             Contract.EndContractBlock();
 
             return InternalEnumerateFileSystemEntries(path, searchPattern, searchOption);
         }
 
-        private static IEnumerable<String> InternalEnumerateFileSystemEntries(String path, String searchPattern, SearchOption searchOption)
+        private static IEnumerable<string> InternalEnumerateFileSystemEntries(string path, string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
 
             return EnumerateFileSystemNames(path, searchPattern, searchOption, true, true);
         }
 
-        private static IEnumerable<String> EnumerateFileSystemNames(String path, String searchPattern, SearchOption searchOption,
+        private static IEnumerable<string> EnumerateFileSystemNames(string path, string searchPattern, SearchOption searchOption,
                                                             bool includeFiles, bool includeDirs)
         {
             Debug.Assert(path != null);
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
-            Contract.Ensures(Contract.Result<IEnumerable<String>>() != null);
+            Contract.Ensures(Contract.Result<IEnumerable<string>>() != null);
 
             return FileSystem.Current.EnumeratePaths(path, searchPattern, searchOption,
                 (includeFiles ? SearchTarget.Files : 0) | (includeDirs ? SearchTarget.Directories : 0));
         }
 
         [System.Security.SecuritySafeCritical]
-        public static String GetDirectoryRoot(String path)
+        public static string GetDirectoryRoot(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             Contract.EndContractBlock();
 
-            String fullPath = Path.GetFullPath(path);
-            String root = fullPath.Substring(0, PathInternal.GetRootLength(fullPath));
+            string fullPath = Path.GetFullPath(path);
+            string root = fullPath.Substring(0, PathInternal.GetRootLength(fullPath));
 
             return root;
         }
 
-        internal static String InternalGetDirectoryRoot(String path)
+        internal static string InternalGetDirectoryRoot(string path)
         {
             if (path == null) return null;
             return path.Substring(0, PathInternal.GetRootLength(path));
@@ -507,14 +498,14 @@ namespace System.IO
        **Exceptions: 
        ==============================================================================*/
         [System.Security.SecuritySafeCritical]
-        public static String GetCurrentDirectory()
+        public static string GetCurrentDirectory()
         {
             return FileSystem.Current.GetCurrentDirectory();
         }
 
 
         [System.Security.SecurityCritical] // auto-generated
-        public static void SetCurrentDirectory(String path)
+        public static void SetCurrentDirectory(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -524,13 +515,13 @@ namespace System.IO
             if (PathInternal.IsPathTooLong(path))
                 throw new PathTooLongException(SR.IO_PathTooLong);
 
-            String fulldestDirName = Path.GetFullPath(path);
+            string fulldestDirName = Path.GetFullPath(path);
 
             FileSystem.Current.SetCurrentDirectory(fulldestDirName);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static void Move(String sourceDirName, String destDirName)
+        public static void Move(string sourceDirName, string destDirName)
         {
             if (sourceDirName == null)
                 throw new ArgumentNullException(nameof(sourceDirName));
@@ -543,25 +534,25 @@ namespace System.IO
                 throw new ArgumentException(SR.Argument_EmptyFileName, nameof(destDirName));
             Contract.EndContractBlock();
 
-            String fullsourceDirName = Path.GetFullPath(sourceDirName);
-            String sourcePath = EnsureTrailingDirectorySeparator(fullsourceDirName);
+            string fullsourceDirName = Path.GetFullPath(sourceDirName);
+            string sourcePath = EnsureTrailingDirectorySeparator(fullsourceDirName);
 
             if (PathInternal.IsDirectoryTooLong(sourcePath))
                 throw new PathTooLongException(SR.IO_PathTooLong);
 
-            String fulldestDirName = Path.GetFullPath(destDirName);
-            String destPath = EnsureTrailingDirectorySeparator(fulldestDirName);
+            string fulldestDirName = Path.GetFullPath(destDirName);
+            string destPath = EnsureTrailingDirectorySeparator(fulldestDirName);
             if (PathInternal.IsDirectoryTooLong(destPath))
                 throw new PathTooLongException(SR.IO_PathTooLong);
 
             StringComparison pathComparison = PathInternal.StringComparison;
 
-            if (String.Equals(sourcePath, destPath, pathComparison))
+            if (string.Equals(sourcePath, destPath, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustBeDifferent);
 
-            String sourceRoot = Path.GetPathRoot(sourcePath);
-            String destinationRoot = Path.GetPathRoot(destPath);
-            if (!String.Equals(sourceRoot, destinationRoot, pathComparison))
+            string sourceRoot = Path.GetPathRoot(sourcePath);
+            string destinationRoot = Path.GetPathRoot(destPath);
+            if (!string.Equals(sourceRoot, destinationRoot, pathComparison))
                 throw new IOException(SR.IO_SourceDestMustHaveSameRoot);
 
             // Windows will throw if the source file/directory doesn't exist, we preemptively check
@@ -576,16 +567,16 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]
-        public static void Delete(String path)
+        public static void Delete(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.RemoveDirectory(fullPath, false);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static void Delete(String path, bool recursive)
+        public static void Delete(string path, bool recursive)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.RemoveDirectory(fullPath, recursive);
         }
 
diff --git a/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs b/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
index 4b4a274997..9842c70f87 100644
--- a/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/DirectoryInfo.cs
@@ -6,7 +6,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.Security;
-using System.Runtime.Serialization;
 
 namespace System.IO
 {
@@ -14,7 +13,7 @@ namespace System.IO
     public sealed partial class DirectoryInfo : FileSystemInfo
     {
         [System.Security.SecuritySafeCritical]
-        public DirectoryInfo(String path)
+        public DirectoryInfo(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -26,7 +25,7 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]
-        internal DirectoryInfo(String fullPath, String originalPath)
+        internal DirectoryInfo(string fullPath, string originalPath)
         {
             Debug.Assert(Path.IsPathRooted(fullPath), "fullPath must be fully qualified!");
 
@@ -36,7 +35,7 @@ namespace System.IO
             DisplayPath = GetDisplayName(OriginalPath);
         }
 
-        public override String Name
+        public override string Name
         {
             get
             {
@@ -68,7 +67,7 @@ namespace System.IO
 
 
         [System.Security.SecuritySafeCritical]
-        public DirectoryInfo CreateSubdirectory(String path)
+        public DirectoryInfo CreateSubdirectory(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -78,16 +77,16 @@ namespace System.IO
         }
 
         [System.Security.SecurityCritical]  // auto-generated
-        private DirectoryInfo CreateSubdirectoryHelper(String path)
+        private DirectoryInfo CreateSubdirectoryHelper(string path)
         {
             Debug.Assert(path != null);
 
             PathHelpers.ThrowIfEmptyOrRootedPath(path);
 
-            String newDirs = Path.Combine(FullPath, path);
-            String fullPath = Path.GetFullPath(newDirs);
+            string newDirs = Path.Combine(FullPath, path);
+            string fullPath = Path.GetFullPath(newDirs);
 
-            if (0 != String.Compare(FullPath, 0, fullPath, 0, FullPath.Length, PathInternal.StringComparison))
+            if (0 != string.Compare(FullPath, 0, fullPath, 0, FullPath.Length, PathInternal.StringComparison))
             {
                 throw new ArgumentException(SR.Format(SR.Argument_InvalidSubPath, path, DisplayPath), nameof(path));
             }
@@ -128,7 +127,7 @@ namespace System.IO
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
         [SecurityCritical]
-        public FileInfo[] GetFiles(String searchPattern)
+        public FileInfo[] GetFiles(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -139,7 +138,7 @@ namespace System.IO
 
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
-        public FileInfo[] GetFiles(String searchPattern, SearchOption searchOption)
+        public FileInfo[] GetFiles(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -152,7 +151,7 @@ namespace System.IO
 
         // Returns an array of Files in the current DirectoryInfo matching the 
         // given search criteria (i.e. "*.txt").
-        private FileInfo[] InternalGetFiles(String searchPattern, SearchOption searchOption)
+        private FileInfo[] InternalGetFiles(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -175,7 +174,7 @@ namespace System.IO
 
         // Returns an array of strongly typed FileSystemInfo entries in the path with the
         // given search criteria (i.e. "*.txt").
-        public FileSystemInfo[] GetFileSystemInfos(String searchPattern)
+        public FileSystemInfo[] GetFileSystemInfos(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -186,7 +185,7 @@ namespace System.IO
 
         // Returns an array of strongly typed FileSystemInfo entries in the path with the
         // given search criteria (i.e. "*.txt").
-        public FileSystemInfo[] GetFileSystemInfos(String searchPattern, SearchOption searchOption)
+        public FileSystemInfo[] GetFileSystemInfos(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -199,7 +198,7 @@ namespace System.IO
 
         // Returns an array of strongly typed FileSystemInfo entries in the path with the
         // given search criteria (i.e. "*.txt").
-        private FileSystemInfo[] InternalGetFileSystemInfos(String searchPattern, SearchOption searchOption)
+        private FileSystemInfo[] InternalGetFileSystemInfos(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -218,7 +217,7 @@ namespace System.IO
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "System*" could match the System & System32
         // directories).
-        public DirectoryInfo[] GetDirectories(String searchPattern)
+        public DirectoryInfo[] GetDirectories(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -230,7 +229,7 @@ namespace System.IO
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "System*" could match the System & System32
         // directories).
-        public DirectoryInfo[] GetDirectories(String searchPattern, SearchOption searchOption)
+        public DirectoryInfo[] GetDirectories(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -244,7 +243,7 @@ namespace System.IO
         // Returns an array of Directories in the current DirectoryInfo matching the 
         // given search criteria (i.e. "System*" could match the System & System32
         // directories).
-        private DirectoryInfo[] InternalGetDirectories(String searchPattern, SearchOption searchOption)
+        private DirectoryInfo[] InternalGetDirectories(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -258,7 +257,7 @@ namespace System.IO
             return InternalEnumerateDirectories("*", SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<DirectoryInfo> EnumerateDirectories(String searchPattern)
+        public IEnumerable<DirectoryInfo> EnumerateDirectories(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -267,7 +266,7 @@ namespace System.IO
             return InternalEnumerateDirectories(searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<DirectoryInfo> EnumerateDirectories(String searchPattern, SearchOption searchOption)
+        public IEnumerable<DirectoryInfo> EnumerateDirectories(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -278,7 +277,7 @@ namespace System.IO
             return InternalEnumerateDirectories(searchPattern, searchOption);
         }
 
-        private IEnumerable<DirectoryInfo> InternalEnumerateDirectories(String searchPattern, SearchOption searchOption)
+        private IEnumerable<DirectoryInfo> InternalEnumerateDirectories(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -291,7 +290,7 @@ namespace System.IO
             return InternalEnumerateFiles("*", SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<FileInfo> EnumerateFiles(String searchPattern)
+        public IEnumerable<FileInfo> EnumerateFiles(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -300,7 +299,7 @@ namespace System.IO
             return InternalEnumerateFiles(searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<FileInfo> EnumerateFiles(String searchPattern, SearchOption searchOption)
+        public IEnumerable<FileInfo> EnumerateFiles(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -311,7 +310,7 @@ namespace System.IO
             return InternalEnumerateFiles(searchPattern, searchOption);
         }
 
-        private IEnumerable<FileInfo> InternalEnumerateFiles(String searchPattern, SearchOption searchOption)
+        private IEnumerable<FileInfo> InternalEnumerateFiles(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -324,7 +323,7 @@ namespace System.IO
             return InternalEnumerateFileSystemInfos("*", SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<FileSystemInfo> EnumerateFileSystemInfos(String searchPattern)
+        public IEnumerable<FileSystemInfo> EnumerateFileSystemInfos(string searchPattern)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -333,7 +332,7 @@ namespace System.IO
             return InternalEnumerateFileSystemInfos(searchPattern, SearchOption.TopDirectoryOnly);
         }
 
-        public IEnumerable<FileSystemInfo> EnumerateFileSystemInfos(String searchPattern, SearchOption searchOption)
+        public IEnumerable<FileSystemInfo> EnumerateFileSystemInfos(string searchPattern, SearchOption searchOption)
         {
             if (searchPattern == null)
                 throw new ArgumentNullException(nameof(searchPattern));
@@ -344,7 +343,7 @@ namespace System.IO
             return InternalEnumerateFileSystemInfos(searchPattern, searchOption);
         }
 
-        private IEnumerable<FileSystemInfo> InternalEnumerateFileSystemInfos(String searchPattern, SearchOption searchOption)
+        private IEnumerable<FileSystemInfo> InternalEnumerateFileSystemInfos(string searchPattern, SearchOption searchOption)
         {
             Debug.Assert(searchPattern != null);
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
@@ -367,7 +366,7 @@ namespace System.IO
             [System.Security.SecuritySafeCritical]
             get
             {
-                String rootPath = Path.GetPathRoot(FullPath);
+                string rootPath = Path.GetPathRoot(FullPath);
 
                 return new DirectoryInfo(rootPath);
             }
@@ -442,12 +441,12 @@ namespace System.IO
         /// <summary>
         /// Returns the original path. Use FullPath or Name properties for the path / directory name.
         /// </summary>
-        public override String ToString()
+        public override string ToString()
         {
             return DisplayPath;
         }
 
-        private static String GetDisplayName(String originalPath)
+        private static string GetDisplayName(string originalPath)
         {
             Debug.Assert(originalPath != null);
 
@@ -458,7 +457,7 @@ namespace System.IO
                 originalPath;
         }
 
-        private static String GetDirName(String fullPath)
+        private static string GetDirName(string fullPath)
         {
             Debug.Assert(fullPath != null);
 
diff --git a/src/System.IO.FileSystem/src/System/IO/DisableMediaInsertionPrompt.cs b/src/System.IO.FileSystem/src/System/IO/DisableMediaInsertionPrompt.cs
new file mode 100644
index 0000000000..ca6261e8e7
--- /dev/null
+++ b/src/System.IO.FileSystem/src/System/IO/DisableMediaInsertionPrompt.cs
@@ -0,0 +1,34 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.IO
+{
+    /// <summary>
+    /// Simple wrapper to safely disable the normal media insertion prompt for
+    /// removable media (floppies, cds, memory cards, etc.)
+    /// </summary>
+    /// <remarks>
+    /// Note that removable media file systems lazily load. After starting the OS
+    /// they won't be loaded until you have media in the drive- and as such the
+    /// prompt won't happen. You have to have had media in at least once to get
+    /// the file system to load and then have removed it.
+    /// </remarks>
+    public sealed class DisableMediaInsertionPrompt : IDisposable
+    {
+        private bool _disableSuccess;
+        private uint _oldMode;
+
+        public DisableMediaInsertionPrompt()
+        {
+            _disableSuccess = Interop.Kernel32.SetThreadErrorMode(Interop.Kernel32.SEM_FAILCRITICALERRORS, out _oldMode);
+        }
+
+        public void Dispose()
+        {
+            uint ignore;
+            if (_disableSuccess)
+                Interop.Kernel32.SetThreadErrorMode(_oldMode, out ignore);
+        }
+    }
+}
diff --git a/src/System.IO.FileSystem/src/System/IO/Error.cs b/src/System.IO.FileSystem/src/System/IO/Error.cs
index c8434ffad8..c0fd1450e2 100644
--- a/src/System.IO.FileSystem/src/System/IO/Error.cs
+++ b/src/System.IO.FileSystem/src/System/IO/Error.cs
@@ -2,16 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
-using System.Runtime.InteropServices;
-using System.Text;
-using System.Globalization;
 using System.Diagnostics.Contracts;
 
 namespace System.IO
 {
     /// <summary>
-    ///     Provides centralized methods for creating exceptions for System.IO.FileSystem.
+    /// Provides centralized methods for creating exceptions for System.IO.FileSystem.
     /// </summary>
     [Pure]
     internal static class Error
diff --git a/src/System.IO.FileSystem/src/System/IO/File.cs b/src/System.IO.FileSystem/src/System/IO/File.cs
index c58fed4c4b..af43f0e260 100644
--- a/src/System.IO.FileSystem/src/System/IO/File.cs
+++ b/src/System.IO.FileSystem/src/System/IO/File.cs
@@ -21,7 +21,7 @@ namespace System.IO
 
         internal const int DefaultBufferSize = 4096;
 
-        public static StreamReader OpenText(String path)
+        public static StreamReader OpenText(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -30,7 +30,7 @@ namespace System.IO
             return new StreamReader(path);
         }
 
-        public static StreamWriter CreateText(String path)
+        public static StreamWriter CreateText(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -39,7 +39,7 @@ namespace System.IO
             return new StreamWriter(path, append: false);
         }
 
-        public static StreamWriter AppendText(String path)
+        public static StreamWriter AppendText(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -51,14 +51,14 @@ namespace System.IO
 
         // Copies an existing file to a new file. An exception is raised if the
         // destination file already exists. Use the 
-        // Copy(String, String, boolean) method to allow 
+        // Copy(string, string, boolean) method to allow 
         // overwriting an existing file.
         //
         // The caller must have certain FileIOPermissions.  The caller must have
         // Read permission to sourceFileName and Create
         // and Write permissions to destFileName.
         // 
-        public static void Copy(String sourceFileName, String destFileName)
+        public static void Copy(string sourceFileName, string destFileName)
         {
             if (sourceFileName == null)
                 throw new ArgumentNullException(nameof(sourceFileName), SR.ArgumentNull_FileName);
@@ -82,7 +82,7 @@ namespace System.IO
         // Read permission to sourceFileName 
         // and Write permissions to destFileName.
         // 
-        public static void Copy(String sourceFileName, String destFileName, bool overwrite)
+        public static void Copy(string sourceFileName, string destFileName, bool overwrite)
         {
             if (sourceFileName == null)
                 throw new ArgumentNullException(nameof(sourceFileName), SR.ArgumentNull_FileName);
@@ -101,15 +101,15 @@ namespace System.IO
         ///    Note: This returns the fully qualified name of the destination file.
         /// </devdoc>
         [System.Security.SecuritySafeCritical]
-        internal static String InternalCopy(String sourceFileName, String destFileName, bool overwrite)
+        internal static string InternalCopy(string sourceFileName, string destFileName, bool overwrite)
         {
             Debug.Assert(sourceFileName != null);
             Debug.Assert(destFileName != null);
             Debug.Assert(sourceFileName.Length > 0);
             Debug.Assert(destFileName.Length > 0);
 
-            String fullSourceFileName = Path.GetFullPath(sourceFileName);
-            String fullDestFileName = Path.GetFullPath(destFileName);
+            string fullSourceFileName = Path.GetFullPath(sourceFileName);
+            string fullDestFileName = Path.GetFullPath(destFileName);
 
             FileSystem.Current.CopyFile(fullSourceFileName, fullDestFileName, overwrite);
 
@@ -138,12 +138,12 @@ namespace System.IO
         // Your application must have Create, Read, and Write permissions to
         // the file.
         // 
-        public static FileStream Create(String path, int bufferSize)
+        public static FileStream Create(string path, int bufferSize)
         {
             return new FileStream(path, FileMode.Create, FileAccess.ReadWrite, FileShare.None, bufferSize);
         }
 
-        public static FileStream Create(String path, int bufferSize, FileOptions options)
+        public static FileStream Create(string path, int bufferSize, FileOptions options)
         {
             return new FileStream(path, FileMode.Create, FileAccess.ReadWrite,
                                   FileShare.None, bufferSize, options);
@@ -159,13 +159,13 @@ namespace System.IO
         // Your application must have Delete permission to the target file.
         // 
         [System.Security.SecuritySafeCritical]
-        public static void Delete(String path)
+        public static void Delete(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
             Contract.EndContractBlock();
 
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
 
             FileSystem.Current.DeleteFile(fullPath);
         }
@@ -179,7 +179,7 @@ namespace System.IO
         // Your application must have Read permission for the target directory.
         // 
         [System.Security.SecuritySafeCritical]
-        public static bool Exists(String path)
+        public static bool Exists(string path)
         {
             try
             {
@@ -210,22 +210,22 @@ namespace System.IO
         }
 
         [System.Security.SecurityCritical]  // auto-generated
-        internal static bool InternalExists(String path)
+        internal static bool InternalExists(string path)
         {
             return FileSystem.Current.FileExists(path);
         }
 
-        public static FileStream Open(String path, FileMode mode)
+        public static FileStream Open(string path, FileMode mode)
         {
             return Open(path, mode, (mode == FileMode.Append ? FileAccess.Write : FileAccess.ReadWrite), FileShare.None);
         }
 
-        public static FileStream Open(String path, FileMode mode, FileAccess access)
+        public static FileStream Open(string path, FileMode mode, FileAccess access)
         {
             return Open(path, mode, access, FileShare.None);
         }
 
-        public static FileStream Open(String path, FileMode mode, FileAccess access, FileShare share)
+        public static FileStream Open(string path, FileMode mode, FileAccess access, FileShare share)
         {
             return new FileStream(path, mode, access, share);
         }
@@ -242,113 +242,112 @@ namespace System.IO
             return dateTime.ToUniversalTime();
         }
 
-        public static void SetCreationTime(String path, DateTime creationTime)
+        public static void SetCreationTime(string path, DateTime creationTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetCreationTime(fullPath, creationTime, asDirectory: false);
         }
 
-        public static void SetCreationTimeUtc(String path, DateTime creationTimeUtc)
+        public static void SetCreationTimeUtc(string path, DateTime creationTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetCreationTime(fullPath, GetUtcDateTimeOffset(creationTimeUtc), asDirectory: false);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static DateTime GetCreationTime(String path)
+        public static DateTime GetCreationTime(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetCreationTime(fullPath).LocalDateTime;
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static DateTime GetCreationTimeUtc(String path)
+        public static DateTime GetCreationTimeUtc(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetCreationTime(fullPath).UtcDateTime;
         }
 
-        public static void SetLastAccessTime(String path, DateTime lastAccessTime)
+        public static void SetLastAccessTime(string path, DateTime lastAccessTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastAccessTime(fullPath, lastAccessTime, asDirectory: false);
         }
 
-        public static void SetLastAccessTimeUtc(String path, DateTime lastAccessTimeUtc)
+        public static void SetLastAccessTimeUtc(string path, DateTime lastAccessTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastAccessTime(fullPath, GetUtcDateTimeOffset(lastAccessTimeUtc), asDirectory: false);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static DateTime GetLastAccessTime(String path)
+        public static DateTime GetLastAccessTime(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetLastAccessTime(fullPath).LocalDateTime;
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static DateTime GetLastAccessTimeUtc(String path)
+        public static DateTime GetLastAccessTimeUtc(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetLastAccessTime(fullPath).UtcDateTime;
         }
 
-        public static void SetLastWriteTime(String path, DateTime lastWriteTime)
+        public static void SetLastWriteTime(string path, DateTime lastWriteTime)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastWriteTime(fullPath, lastWriteTime, asDirectory: false);
         }
 
-        public static void SetLastWriteTimeUtc(String path, DateTime lastWriteTimeUtc)
+        public static void SetLastWriteTimeUtc(string path, DateTime lastWriteTimeUtc)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetLastWriteTime(fullPath, GetUtcDateTimeOffset(lastWriteTimeUtc), asDirectory: false);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static DateTime GetLastWriteTime(String path)
+        public static DateTime GetLastWriteTime(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetLastWriteTime(fullPath).LocalDateTime;
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static DateTime GetLastWriteTimeUtc(String path)
+        public static DateTime GetLastWriteTimeUtc(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetLastWriteTime(fullPath).UtcDateTime;
         }
 
         [System.Security.SecuritySafeCritical]
-        public static FileAttributes GetAttributes(String path)
+        public static FileAttributes GetAttributes(string path)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             return FileSystem.Current.GetAttributes(fullPath);
         }
 
         [System.Security.SecurityCritical]
-        public static void SetAttributes(String path, FileAttributes fileAttributes)
+        public static void SetAttributes(string path, FileAttributes fileAttributes)
         {
-            String fullPath = Path.GetFullPath(path);
+            string fullPath = Path.GetFullPath(path);
             FileSystem.Current.SetAttributes(fullPath, fileAttributes);
         }
 
         [System.Security.SecuritySafeCritical]
-        public static FileStream OpenRead(String path)
+        public static FileStream OpenRead(string path)
         {
             return new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
         }
 
-
-        public static FileStream OpenWrite(String path)
+        public static FileStream OpenWrite(string path)
         {
             return new FileStream(path, FileMode.OpenOrCreate,
                                   FileAccess.Write, FileShare.None);
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static String ReadAllText(String path)
+        public static string ReadAllText(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -360,7 +359,7 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static String ReadAllText(String path, Encoding encoding)
+        public static string ReadAllText(string path, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -374,7 +373,7 @@ namespace System.IO
         }
 
         [System.Security.SecurityCritical]
-        private static String InternalReadAllText(String path, Encoding encoding)
+        private static string InternalReadAllText(string path, Encoding encoding)
         {
             Debug.Assert(path != null);
             Debug.Assert(encoding != null);
@@ -385,7 +384,7 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static void WriteAllText(String path, String contents)
+        public static void WriteAllText(string path, string contents)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -400,7 +399,7 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static void WriteAllText(String path, String contents, Encoding encoding)
+        public static void WriteAllText(string path, string contents, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -417,19 +416,19 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static byte[] ReadAllBytes(String path)
+        public static byte[] ReadAllBytes(string path)
         {
             return InternalReadAllBytes(path);
         }
 
         [System.Security.SecurityCritical]
-        private static byte[] InternalReadAllBytes(String path)
+        private static byte[] InternalReadAllBytes(string path)
         {
             // bufferSize == 1 used to avoid unnecessary buffer in FileStream
             using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, bufferSize: 1))
             {
                 long fileLength = fs.Length;
-                if (fileLength > Int32.MaxValue)
+                if (fileLength > int.MaxValue)
                     throw new IOException(SR.IO_FileTooLong2GB);
 
                 int index = 0;
@@ -448,7 +447,7 @@ namespace System.IO
         }
 
         [System.Security.SecuritySafeCritical]  // auto-generated
-        public static void WriteAllBytes(String path, byte[] bytes)
+        public static void WriteAllBytes(string path, byte[] bytes)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path), SR.ArgumentNull_Path);
@@ -462,7 +461,7 @@ namespace System.IO
         }
 
         [System.Security.SecurityCritical]
-        private static void InternalWriteAllBytes(String path, byte[] bytes)
+        private static void InternalWriteAllBytes(string path, byte[] bytes)
         {
             Debug.Assert(path != null);
             Debug.Assert(path.Length != 0);
@@ -473,7 +472,7 @@ namespace System.IO
                 fs.Write(bytes, 0, bytes.Length);
             }
         }
-        public static String[] ReadAllLines(String path)
+        public static string[] ReadAllLines(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -484,7 +483,7 @@ namespace System.IO
             return InternalReadAllLines(path, Encoding.UTF8);
         }
 
-        public static String[] ReadAllLines(String path, Encoding encoding)
+        public static string[] ReadAllLines(string path, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -497,14 +496,14 @@ namespace System.IO
             return InternalReadAllLines(path, encoding);
         }
 
-        private static String[] InternalReadAllLines(String path, Encoding encoding)
+        private static string[] InternalReadAllLines(string path, Encoding encoding)
         {
             Debug.Assert(path != null);
             Debug.Assert(encoding != null);
             Debug.Assert(path.Length != 0);
 
-            String line;
-            List<String> lines = new List<String>();
+            string line;
+            List<string> lines = new List<string>();
 
             using (StreamReader sr = new StreamReader(path, encoding))
                 while ((line = sr.ReadLine()) != null)
@@ -513,7 +512,7 @@ namespace System.IO
             return lines.ToArray();
         }
 
-        public static IEnumerable<String> ReadLines(String path)
+        public static IEnumerable<string> ReadLines(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -524,7 +523,7 @@ namespace System.IO
             return ReadLinesIterator.CreateIterator(path, Encoding.UTF8);
         }
 
-        public static IEnumerable<String> ReadLines(String path, Encoding encoding)
+        public static IEnumerable<string> ReadLines(string path, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -537,12 +536,12 @@ namespace System.IO
             return ReadLinesIterator.CreateIterator(path, encoding);
         }
 
-        public static void WriteAllLines(String path, String[] contents)
+        public static void WriteAllLines(string path, string[] contents)
         {
-            WriteAllLines(path, (IEnumerable<String>)contents);
+            WriteAllLines(path, (IEnumerable<string>)contents);
         }
 
-        public static void WriteAllLines(String path, IEnumerable<String> contents)
+        public static void WriteAllLines(string path, IEnumerable<string> contents)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -555,12 +554,12 @@ namespace System.IO
             InternalWriteAllLines(new StreamWriter(path), contents);
         }
 
-        public static void WriteAllLines(String path, String[] contents, Encoding encoding)
+        public static void WriteAllLines(string path, string[] contents, Encoding encoding)
         {
-            WriteAllLines(path, (IEnumerable<String>)contents, encoding);
+            WriteAllLines(path, (IEnumerable<string>)contents, encoding);
         }
 
-        public static void WriteAllLines(String path, IEnumerable<String> contents, Encoding encoding)
+        public static void WriteAllLines(string path, IEnumerable<string> contents, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -575,21 +574,21 @@ namespace System.IO
             InternalWriteAllLines(new StreamWriter(path, false, encoding), contents);
         }
 
-        private static void InternalWriteAllLines(TextWriter writer, IEnumerable<String> contents)
+        private static void InternalWriteAllLines(TextWriter writer, IEnumerable<string> contents)
         {
             Debug.Assert(writer != null);
             Debug.Assert(contents != null);
 
             using (writer)
             {
-                foreach (String line in contents)
+                foreach (string line in contents)
                 {
                     writer.WriteLine(line);
                 }
             }
         }
 
-        public static void AppendAllText(String path, String contents)
+        public static void AppendAllText(string path, string contents)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -603,7 +602,7 @@ namespace System.IO
             }
         }
 
-        public static void AppendAllText(String path, String contents, Encoding encoding)
+        public static void AppendAllText(string path, string contents, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -619,7 +618,7 @@ namespace System.IO
             }
         }
 
-        public static void AppendAllLines(String path, IEnumerable<String> contents)
+        public static void AppendAllLines(string path, IEnumerable<string> contents)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -632,7 +631,7 @@ namespace System.IO
             InternalWriteAllLines(new StreamWriter(path, append: true), contents);
         }
 
-        public static void AppendAllLines(String path, IEnumerable<String> contents, Encoding encoding)
+        public static void AppendAllLines(string path, IEnumerable<string> contents, Encoding encoding)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -647,12 +646,12 @@ namespace System.IO
             InternalWriteAllLines(new StreamWriter(path, true, encoding), contents);
         }
 
-        public static void Replace(String sourceFileName, String destinationFileName, String destinationBackupFileName)
+        public static void Replace(string sourceFileName, string destinationFileName, string destinationBackupFileName)
         {
             Replace(sourceFileName, destinationFileName, destinationBackupFileName, ignoreMetadataErrors: false);
         }
 
-        public static void Replace(String sourceFileName, String destinationFileName, String destinationBackupFileName, bool ignoreMetadataErrors)
+        public static void Replace(string sourceFileName, string destinationFileName, string destinationBackupFileName, bool ignoreMetadataErrors)
         {
             if (sourceFileName == null)
                 throw new ArgumentNullException(nameof(sourceFileName));
@@ -675,7 +674,7 @@ namespace System.IO
         // permissions to destFileName.
         // 
         [System.Security.SecuritySafeCritical]
-        public static void Move(String sourceFileName, String destFileName)
+        public static void Move(string sourceFileName, string destFileName)
         {
             if (sourceFileName == null)
                 throw new ArgumentNullException(nameof(sourceFileName), SR.ArgumentNull_FileName);
@@ -687,8 +686,8 @@ namespace System.IO
                 throw new ArgumentException(SR.Argument_EmptyFileName, nameof(destFileName));
             Contract.EndContractBlock();
 
-            String fullSourceFileName = Path.GetFullPath(sourceFileName);
-            String fullDestFileName = Path.GetFullPath(destFileName);
+            string fullSourceFileName = Path.GetFullPath(sourceFileName);
+            string fullDestFileName = Path.GetFullPath(destFileName);
 
             if (!InternalExists(fullSourceFileName))
             {
@@ -698,7 +697,7 @@ namespace System.IO
             FileSystem.Current.MoveFile(fullSourceFileName, fullDestFileName);
         }
 
-        public static void Encrypt(String path)
+        public static void Encrypt(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -711,7 +710,7 @@ namespace System.IO
             throw new PlatformNotSupportedException(SR.PlatformNotSupported_FileEncryption);
         }
 
-        public static void Decrypt(String path)
+        public static void Decrypt(string path)
         {
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
@@ -907,7 +906,7 @@ namespace System.IO
                 : InternalWriteAllBytesAsync(path, bytes, cancellationToken);
         }
 
-        private static async Task InternalWriteAllBytesAsync(String path, byte[] bytes, CancellationToken cancellationToken)
+        private static async Task InternalWriteAllBytesAsync(string path, byte[] bytes, CancellationToken cancellationToken)
         {
             Debug.Assert(!string.IsNullOrEmpty(path));
             Debug.Assert(bytes != null);
diff --git a/src/System.IO.FileSystem/src/System/IO/FileInfo.cs b/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
index e13fcfe9f5..0a3540bace 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileInfo.cs
@@ -2,13 +2,8 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
-using System.Globalization;
-using System.Runtime.InteropServices;
-using System.Runtime.Serialization;
-using System.Runtime.Versioning;
 using System.Text;
 
 namespace System.IO
@@ -18,13 +13,13 @@ namespace System.IO
     [Serializable]
     public sealed partial class FileInfo : FileSystemInfo
     {
-        private String _name;
+        private string _name;
 
         [System.Security.SecurityCritical]
         private FileInfo() { }
 
         [System.Security.SecuritySafeCritical]
-        public FileInfo(String fileName)
+        public FileInfo(string fileName)
         {
             if (fileName == null)
                 throw new ArgumentNullException(nameof(fileName));
@@ -34,24 +29,24 @@ namespace System.IO
         }
 
         [System.Security.SecurityCritical]
-        private void Init(String fileName)
+        private void Init(string fileName)
         {
             OriginalPath = fileName;
             // Must fully qualify the path for the security check
-            String fullPath = Path.GetFullPath(fileName);
+            string fullPath = Path.GetFullPath(fileName);
 
             _name = Path.GetFileName(fileName);
             FullPath = fullPath;
             DisplayPath = GetDisplayPath(fileName);
         }
 
-        private String GetDisplayPath(String originalPath)
+        private string GetDisplayPath(string originalPath)
         {
             return originalPath;
         }
 
         [System.Security.SecuritySafeCritical]
-        internal FileInfo(String fullPath, String originalPath)
+        internal FileInfo(string fullPath, string originalPath)
         {
             Debug.Assert(Path.IsPathRooted(fullPath), "fullPath must be fully qualified!");
             _name = originalPath ?? Path.GetFileName(fullPath);
@@ -60,7 +55,7 @@ namespace System.IO
             DisplayPath = _name;
         }
 
-        public override String Name
+        public override string Name
         {
             get { return _name; }
         }
@@ -80,7 +75,7 @@ namespace System.IO
         }
 
         /* Returns the name of the directory that the file is in */
-        public String DirectoryName
+        public string DirectoryName
         {
             [System.Security.SecuritySafeCritical]
             get
@@ -94,7 +89,7 @@ namespace System.IO
         {
             get
             {
-                String dirName = DirectoryName;
+                string dirName = DirectoryName;
                 if (dirName == null)
                     return null;
                 return new DirectoryInfo(dirName);
@@ -135,14 +130,14 @@ namespace System.IO
 
         // Copies an existing file to a new file. An exception is raised if the
         // destination file already exists. Use the 
-        // Copy(String, String, boolean) method to allow 
+        // Copy(string, string, boolean) method to allow 
         // overwriting an existing file.
         //
         // The caller must have certain FileIOPermissions.  The caller must have
         // Read permission to sourceFileName 
         // and Write permissions to destFileName.
         // 
-        public FileInfo CopyTo(String destFileName)
+        public FileInfo CopyTo(string destFileName)
         {
             if (destFileName == null)
                 throw new ArgumentNullException(nameof(destFileName), SR.ArgumentNull_FileName);
@@ -164,7 +159,7 @@ namespace System.IO
         // Read permission to sourceFileName and Create
         // and Write permissions to destFileName.
         // 
-        public FileInfo CopyTo(String destFileName, bool overwrite)
+        public FileInfo CopyTo(string destFileName, bool overwrite)
         {
             if (destFileName == null)
                 throw new ArgumentNullException(nameof(destFileName), SR.ArgumentNull_FileName);
@@ -234,7 +229,6 @@ namespace System.IO
             return new FileStream(FullPath, mode, access, share);
         }
 
-
         [System.Security.SecuritySafeCritical]  // auto-generated
         public FileStream OpenRead()
         {
@@ -242,7 +236,6 @@ namespace System.IO
                                   FileShare.Read, 4096, false);
         }
 
-
         public FileStream OpenWrite()
         {
             return new FileStream(FullPath, FileMode.OpenOrCreate,
@@ -258,7 +251,7 @@ namespace System.IO
         // permissions to destFileName.
         // 
         [System.Security.SecuritySafeCritical]
-        public void MoveTo(String destFileName)
+        public void MoveTo(string destFileName)
         {
             if (destFileName == null)
                 throw new ArgumentNullException(nameof(destFileName));
@@ -266,7 +259,7 @@ namespace System.IO
                 throw new ArgumentException(SR.Argument_EmptyFileName, nameof(destFileName));
             Contract.EndContractBlock();
 
-            String fullDestFileName = Path.GetFullPath(destFileName);
+            string fullDestFileName = Path.GetFullPath(destFileName);
 
             // These checks are in place to ensure Unix error throwing happens the same way
             // as it does on Windows.These checks can be removed if a solution to #2460 is
@@ -290,19 +283,19 @@ namespace System.IO
             Invalidate();
         }
 
-        public FileInfo Replace(String destinationFileName, String destinationBackupFileName)
+        public FileInfo Replace(string destinationFileName, string destinationBackupFileName)
         {
             return Replace(destinationFileName, destinationBackupFileName, ignoreMetadataErrors: false);
         }
 
-        public FileInfo Replace(String destinationFileName, String destinationBackupFileName, bool ignoreMetadataErrors)
+        public FileInfo Replace(string destinationFileName, string destinationBackupFileName, bool ignoreMetadataErrors)
         {
             File.Replace(FullPath, destinationFileName, destinationBackupFileName, ignoreMetadataErrors);
             return new FileInfo(destinationFileName);
         }
 
         // Returns the display path
-        public override String ToString()
+        public override string ToString()
         {
             return DisplayPath;
         }
diff --git a/src/System.IO.FileSystem/src/System/IO/FileSystem.cs b/src/System.IO.FileSystem/src/System/IO/FileSystem.cs
index 87b304e4f5..9e3056e2cc 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileSystem.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileSystem.cs
@@ -21,7 +21,6 @@ namespace System.IO
         public abstract void ReplaceFile(string sourceFullPath, string destFullPath, string destBackupFullPath, bool ignoreMetadataErrors);
         public abstract void DeleteFile(string fullPath);
         public abstract bool FileExists(string fullPath);
-        public abstract FileStream Open(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent);
         public abstract void MoveFile(string sourceFullPath, string destFullPath);
 
         public abstract FileAttributes GetAttributes(string fullPath);
@@ -42,8 +41,6 @@ namespace System.IO
         // Path
         public abstract string GetCurrentDirectory();
         public abstract void SetCurrentDirectory(string fullPath);
-        public abstract int MaxPath { get; }
-        public abstract int MaxDirectoryPath { get; }
 
         // Volume
         public abstract string[] GetLogicalDrives();
diff --git a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.Windows.cs b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.Windows.cs
index 3c6aa499c5..301425c7df 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.Windows.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.Windows.cs
@@ -126,7 +126,7 @@ namespace System.IO
         {
             // This should not throw, instead we store the result so that we can throw it
             // when someone actually accesses a property
-            _dataInitialized = Win32FileSystem.FillAttributeInfo(FullPath, ref _data, tryagain: false, returnErrorOnNotFound: false);
+            _dataInitialized = Win32FileSystem.FillAttributeInfo(FullPath, ref _data, returnErrorOnNotFound: false);
         }
     }
 }
diff --git a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
index 5002a4c828..268eb289d9 100644
--- a/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
+++ b/src/System.IO.FileSystem/src/System/IO/FileSystemInfo.cs
@@ -16,9 +16,9 @@ namespace System.IO
     [Serializable]
     public abstract partial class FileSystemInfo : MarshalByRefObject, ISerializable
     {
-        protected String FullPath;          // fully qualified path of the file or directory
-        protected String OriginalPath;      // path passed in by the user
-        private String _displayPath = "";   // path that can be displayed to the user
+        protected string FullPath;          // fully qualified path of the file or directory
+        protected string OriginalPath;      // path passed in by the user
+        private string _displayPath = "";   // path that can be displayed to the user
 
         [System.Security.SecurityCritical]
         protected FileSystemInfo()
@@ -36,7 +36,7 @@ namespace System.IO
         }
 
         // Full path of the directory/file
-        public virtual String FullName
+        public virtual string FullName
         {
             [System.Security.SecuritySafeCritical]
             get
@@ -45,7 +45,7 @@ namespace System.IO
             }
         }
 
-        public String Extension
+        public string Extension
         {
             get
             {
@@ -59,13 +59,13 @@ namespace System.IO
                     if (PathInternal.IsDirectorySeparator(ch) || ch == Path.VolumeSeparatorChar)
                         break;
                 }
-                return String.Empty;
+                return string.Empty;
             }
         }
 
         // For files name of the file is returned, for directories the last directory in hierarchy is returned if possible,
         // otherwise the fully qualified name s returned
-        public abstract String Name
+        public abstract string Name
         {
             get;
         }
@@ -181,7 +181,7 @@ namespace System.IO
             }
         }
 
-        internal String DisplayPath
+        internal string DisplayPath
         {
             get
             {
diff --git a/src/System.IO.FileSystem/src/System/IO/MultiplexingWin32WinRTFileSystem.cs b/src/System.IO.FileSystem/src/System/IO/MultiplexingWin32WinRTFileSystem.cs
index 9f4715fcd5..83ffc18458 100644
--- a/src/System.IO.FileSystem/src/System/IO/MultiplexingWin32WinRTFileSystem.cs
+++ b/src/System.IO.FileSystem/src/System/IO/MultiplexingWin32WinRTFileSystem.cs
@@ -20,9 +20,6 @@ namespace System.IO
                 (IFileSystemObject)caller;
         }
 
-        public override int MaxPath { get { return Interop.Kernel32.MAX_PATH; } }
-        public override int MaxDirectoryPath { get { return Interop.Kernel32.MAX_DIRECTORY_PATH; } }
-
         public override void CopyFile(string sourceFullPath, string destFullPath, bool overwrite)
         {
             Select(sourceFullPath, destFullPath).CopyFile(sourceFullPath, destFullPath, overwrite);
@@ -105,12 +102,6 @@ namespace System.IO
             Select(sourceFullPath, destFullPath).MoveFile(sourceFullPath, destFullPath);
         }
 
-        public override FileStreamBase Open(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent)
-        {
-            bool isCreate = mode != FileMode.Open && mode != FileMode.Truncate;
-            return Select(fullPath, isCreate).Open(fullPath, mode, access, share, bufferSize, options, parent);
-        }
-
         public override void RemoveDirectory(string fullPath, bool recursive)
         {
             Select(fullPath).RemoveDirectory(fullPath, recursive);
@@ -235,7 +226,7 @@ namespace System.IO
                 // the parent directory, so we walk up the path.
                 fullPath = PathHelpers.GetDirectoryNameInternal(fullPath);
                 // only walk up the path if we are creating a file/directory and not at the root
-            } while (isCreate && !String.IsNullOrEmpty(fullPath));
+            } while (isCreate && !string.IsNullOrEmpty(fullPath));
 
             return useWinRt;
         }
diff --git a/src/System.IO.FileSystem/src/System/IO/PathHelpers.Windows.cs b/src/System.IO.FileSystem/src/System/IO/PathHelpers.Windows.cs
index c0c3cc12ab..a8da668317 100644
--- a/src/System.IO.FileSystem/src/System/IO/PathHelpers.Windows.cs
+++ b/src/System.IO.FileSystem/src/System/IO/PathHelpers.Windows.cs
@@ -9,7 +9,7 @@ namespace System.IO
     internal static partial class PathHelpers
     {
         // Trim trailing whitespace, tabs etc but don't be aggressive in removing everything that has UnicodeCategory of trailing space.
-        // String.WhitespaceChars will trim more aggressively than what the underlying FS does (for ex, NTFS, FAT).    
+        // string.WhitespaceChars will trim more aggressively than what the underlying FS does (for ex, NTFS, FAT).    
         internal static readonly char[] TrimEndChars = { (char)0x9, (char)0xA, (char)0xB, (char)0xC, (char)0xD, (char)0x20, (char)0x85, (char)0xA0 };
         internal static readonly char[] TrimStartChars = { ' ' };
 
diff --git a/src/System.IO.FileSystem/src/System/IO/PathHelpers.cs b/src/System.IO.FileSystem/src/System/IO/PathHelpers.cs
index bc73175ff4..b6d966731e 100644
--- a/src/System.IO.FileSystem/src/System/IO/PathHelpers.cs
+++ b/src/System.IO.FileSystem/src/System/IO/PathHelpers.cs
@@ -11,8 +11,8 @@ namespace System.IO
         // Array of the separator chars
         internal static readonly char[] DirectorySeparatorChars = new char[] { Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar };
 
-        // String-representation of the directory-separator character, used when appending the character to another
-        // string so as to avoid the boxing of the character when calling String.Concat(..., object).
+        // string-representation of the directory-separator character, used when appending the character to another
+        // string so as to avoid the boxing of the character when calling string.Concat(..., object).
         internal static readonly string DirectorySeparatorCharAsString = Path.DirectorySeparatorChar.ToString();
 
         // System.IO.Path has both public Combine and internal InternalCombine
@@ -34,7 +34,7 @@ namespace System.IO
             return path.Length == PathInternal.GetRootLength(path);
         }
 
-        internal static bool EndsInDirectorySeparator(String path)
+        internal static bool EndsInDirectorySeparator(string path)
         {
             return path.Length > 0 && PathInternal.IsDirectorySeparator(path[path.Length - 1]);
         }
diff --git a/src/System.IO.FileSystem/src/System/IO/UnixFileSystem.cs b/src/System.IO.FileSystem/src/System/IO/UnixFileSystem.cs
index 91df2c7c90..958d91037d 100644
--- a/src/System.IO.FileSystem/src/System/IO/UnixFileSystem.cs
+++ b/src/System.IO.FileSystem/src/System/IO/UnixFileSystem.cs
@@ -15,15 +15,6 @@ namespace System.IO
     {
         internal const int DefaultBufferSize = 4096;
 
-        public override int MaxPath { get { return Interop.Sys.MaxPath; } }
-
-        public override int MaxDirectoryPath { get { return Interop.Sys.MaxPath; } }
-
-        public override FileStream Open(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent)
-        {
-            return new FileStream(fullPath, mode, access, share, bufferSize, options);
-        }
-
         public override void CopyFile(string sourceFullPath, string destFullPath, bool overwrite)
         {
             // The destination path may just be a directory into which the file should be copied.
@@ -238,7 +229,7 @@ namespace System.IO
             while (stackDir.Count > 0)
             {
                 string name = stackDir.Pop();
-                if (name.Length >= MaxDirectoryPath)
+                if (name.Length >= Interop.Sys.MaxPath)
                 {
                     throw new PathTooLongException(SR.IO_PathTooLong);
                 }
diff --git a/src/System.IO.FileSystem/src/System/IO/Win32FileSystem.cs b/src/System.IO.FileSystem/src/System/IO/Win32FileSystem.cs
index a2a6733554..7342c9c401 100644
--- a/src/System.IO.FileSystem/src/System/IO/Win32FileSystem.cs
+++ b/src/System.IO.FileSystem/src/System/IO/Win32FileSystem.cs
@@ -13,9 +13,6 @@ namespace System.IO
     {
         internal const int GENERIC_READ = unchecked((int)0x80000000);
 
-        public override int MaxPath { get { return Interop.Kernel32.MAX_PATH; } }
-        public override int MaxDirectoryPath { get { return Interop.Kernel32.MAX_DIRECTORY_PATH; } }
-
         public override void CopyFile(string sourceFullPath, string destFullPath, bool overwrite)
         {
             Interop.Kernel32.SECURITY_ATTRIBUTES secAttrs = default(Interop.Kernel32.SECURITY_ATTRIBUTES);
@@ -99,7 +96,7 @@ namespace System.IO
                 int i = length - 1;
                 while (i >= lengthRoot && !somepathexists)
                 {
-                    String dir = fullPath.Substring(0, i + 1);
+                    string dir = fullPath.Substring(0, i + 1);
 
                     if (!DirectoryExists(dir)) // Create only the ones missing
                         stackDir.Add(dir);
@@ -119,12 +116,12 @@ namespace System.IO
 
             bool r = true;
             int firstError = 0;
-            String errorString = fullPath;
+            string errorString = fullPath;
 
             // If all the security checks succeeded create all the directories
             while (stackDir.Count > 0)
             {
-                String name = stackDir[stackDir.Count - 1];
+                string name = stackDir[stackDir.Count - 1];
                 stackDir.RemoveAt(stackDir.Count - 1);
 
                 r = Interop.Kernel32.CreateDirectory(name, ref secAttrs);
@@ -157,7 +154,7 @@ namespace System.IO
             // Handle CreateDirectory("X:\\") when X: doesn't exist. Similarly for n/w paths.
             if ((count == 0) && !somepathexists)
             {
-                String root = Directory.InternalGetDirectoryRoot(fullPath);
+                string root = Directory.InternalGetDirectoryRoot(fullPath);
                 if (!DirectoryExists(root))
                     throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_PATH_NOT_FOUND, root);
                 return;
@@ -169,7 +166,7 @@ namespace System.IO
                 throw Win32Marshal.GetExceptionForWin32Error(firstError, errorString);
         }
 
-        public override void DeleteFile(System.String fullPath)
+        public override void DeleteFile(string fullPath)
         {
             bool r = Interop.Kernel32.DeleteFile(fullPath);
             if (!r)
@@ -188,10 +185,10 @@ namespace System.IO
             return DirectoryExists(fullPath, out lastError);
         }
 
-        private bool DirectoryExists(String path, out int lastError)
+        private bool DirectoryExists(string path, out int lastError)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            lastError = FillAttributeInfo(path, ref data, false, true);
+            lastError = FillAttributeInfo(path, ref data, returnErrorOnNotFound: true);
 
             return (lastError == 0) && (data.fileAttributes != -1)
                     && ((data.fileAttributes & Interop.Kernel32.FileAttributes.FILE_ATTRIBUTE_DIRECTORY) != 0);
@@ -220,128 +217,68 @@ namespace System.IO
             }
         }
 
-        // Returns 0 on success, otherwise a Win32 error code.  Note that
-        // classes should use -1 as the uninitialized state for dataInitialized.
-        [System.Security.SecurityCritical]  // auto-generated
-        internal static int FillAttributeInfo(String path, ref Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data, bool tryagain, bool returnErrorOnNotFound)
+        /// <summary>
+        /// Returns 0 on success, otherwise a Win32 error code.  Note that
+        /// classes should use -1 as the uninitialized state for dataInitialized.
+        /// </summary>
+        /// <param name="returnErrorOnNotFound">Return the error code for not found errors?</param>
+        [System.Security.SecurityCritical]
+        internal static int FillAttributeInfo(string path, ref Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data, bool returnErrorOnNotFound)
         {
-            int errorCode = 0;
-            if (tryagain) // someone has a handle to the file open, or other error
+            int errorCode = Interop.Errors.ERROR_SUCCESS;
+
+            // Neither GetFileAttributes or FindFirstFile like trailing separators
+            path = path.TrimEnd(PathHelpers.DirectorySeparatorChars);
+
+            using (new DisableMediaInsertionPrompt())
             {
-                Interop.Kernel32.WIN32_FIND_DATA findData;
-                findData = new Interop.Kernel32.WIN32_FIND_DATA();
-
-                // Remove trailing slash since this can cause grief to FindFirstFile. You will get an invalid argument error
-                String tempPath = path.TrimEnd(PathHelpers.DirectorySeparatorChars);
-
-                // For removable media drives, normally the OS will pop up a dialog requesting insertion
-                // of the relevant media (CD, floppy, memory card, etc.). We don't want this prompt so we
-                // set SEM_FAILCRITICALERRORS to suppress it.
-                //
-                // Note that said dialog only shows once the relevant filesystem has been loaded, which
-                // does not happen until actual media is accessed at least once since booting.
-
-                uint oldMode;
-                bool success = Interop.Kernel32.SetThreadErrorMode(Interop.Kernel32.SEM_FAILCRITICALERRORS, out oldMode);
-                try
+                if (!Interop.Kernel32.GetFileAttributesEx(path, Interop.Kernel32.GET_FILEEX_INFO_LEVELS.GetFileExInfoStandard, ref data))
                 {
-                    bool error = false;
-                    SafeFindHandle handle = Interop.Kernel32.FindFirstFile(tempPath, ref findData);
-                    try
+                    errorCode = Marshal.GetLastWin32Error();
+                    if (errorCode == Interop.Errors.ERROR_ACCESS_DENIED)
                     {
-                        if (handle.IsInvalid)
-                        {
-                            error = true;
-                            errorCode = Marshal.GetLastWin32Error();
+                        // Files that are marked for deletion will not let you GetFileAttributes,
+                        // ERROR_ACCESS_DENIED is given back without filling out the data struct.
+                        // FindFirstFile, however, will. Historically we always gave back attributes
+                        // for marked-for-deletion files.
 
-                            if (errorCode == Interop.Errors.ERROR_FILE_NOT_FOUND ||
-                                errorCode == Interop.Errors.ERROR_PATH_NOT_FOUND ||
-                                errorCode == Interop.Errors.ERROR_NOT_READY)  // Removable media not inserted
+                        var findData = new Interop.Kernel32.WIN32_FIND_DATA();
+                        using (SafeFindHandle handle = Interop.Kernel32.FindFirstFile(path, ref findData))
+                        {
+                            if (handle.IsInvalid)
                             {
-                                if (!returnErrorOnNotFound)
-                                {
-                                    // Return default value for backward compatibility
-                                    errorCode = 0;
-                                    data.fileAttributes = -1;
-                                }
+                                errorCode = Marshal.GetLastWin32Error();
                             }
-                            return errorCode;
-                        }
-                    }
-                    finally
-                    {
-                        // Close the Win32 handle
-                        try
-                        {
-                            handle.Dispose();
-                        }
-                        catch
-                        {
-                            // if we're already returning an error, don't throw another one. 
-                            if (!error)
+                            else
                             {
-                                throw Win32Marshal.GetExceptionForLastWin32Error();
+                                errorCode = Interop.Errors.ERROR_SUCCESS;
+                                data.PopulateFrom(ref findData);
                             }
                         }
                     }
                 }
-                finally
-                {
-                    if (success)
-                        Interop.Kernel32.SetThreadErrorMode(oldMode, out oldMode);
-                }
-
-                // Copy the information to data
-                data.PopulateFrom(ref findData);
             }
-            else
+
+            if (errorCode != Interop.Errors.ERROR_SUCCESS && !returnErrorOnNotFound)
             {
-                // For floppy drives, normally the OS will pop up a dialog saying
-                // there is no disk in drive A:, please insert one.  We don't want that.
-                // SetErrorMode will let us disable this, but we should set the error
-                // mode back, since this may have wide-ranging effects.
-                bool success = false;
-                uint oldMode;
-                bool errorModeSuccess = Interop.Kernel32.SetThreadErrorMode(Interop.Kernel32.SEM_FAILCRITICALERRORS, out oldMode);
-                try
+                switch (errorCode)
                 {
-                    success = Interop.Kernel32.GetFileAttributesEx(path, Interop.Kernel32.GET_FILEEX_INFO_LEVELS.GetFileExInfoStandard, ref data);
-                }
-                finally
-                {
-                    if (errorModeSuccess)
-                        Interop.Kernel32.SetThreadErrorMode(oldMode, out oldMode);
-                }
-
-                if (!success)
-                {
-                    errorCode = Marshal.GetLastWin32Error();
-                    if (errorCode != Interop.Errors.ERROR_FILE_NOT_FOUND &&
-                        errorCode != Interop.Errors.ERROR_PATH_NOT_FOUND &&
-                        errorCode != Interop.Errors.ERROR_NOT_READY)  // floppy device not ready
-                    {
-                        // In case someone latched onto the file. Take the perf hit only for failure
-                        return FillAttributeInfo(path, ref data, true, returnErrorOnNotFound);
-                    }
-                    else
-                    {
-                        if (!returnErrorOnNotFound)
-                        {
-                            // Return default value for backward compatibility
-                            errorCode = 0;
-                            data.fileAttributes = -1;
-                        }
-                    }
+                    case Interop.Errors.ERROR_FILE_NOT_FOUND:
+                    case Interop.Errors.ERROR_PATH_NOT_FOUND:
+                    case Interop.Errors.ERROR_NOT_READY: // Removable media not ready
+                        // Return default value for backward compatibility
+                        data.fileAttributes = -1;
+                        return Interop.Errors.ERROR_SUCCESS;
                 }
             }
 
             return errorCode;
         }
 
-        public override bool FileExists(System.String fullPath)
+        public override bool FileExists(string fullPath)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, true);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: true);
 
             return (errorCode == 0) && (data.fileAttributes != -1)
                     && ((data.fileAttributes & Interop.Kernel32.FileAttributes.FILE_ATTRIBUTE_DIRECTORY) == 0);
@@ -350,7 +287,7 @@ namespace System.IO
         public override FileAttributes GetAttributes(string fullPath)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, true);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: true);
             if (errorCode != 0)
                 throw Win32Marshal.GetExceptionForWin32Error(errorCode, fullPath);
 
@@ -362,7 +299,7 @@ namespace System.IO
             StringBuilder sb = StringBuilderCache.Acquire(Interop.Kernel32.MAX_PATH + 1);
             if (Interop.Kernel32.GetCurrentDirectory(sb.Capacity, sb) == 0)
                 throw Win32Marshal.GetExceptionForLastWin32Error();
-            String currentDirectory = sb.ToString();
+            string currentDirectory = sb.ToString();
             // Note that if we have somehow put our command prompt into short
             // file name mode (i.e. by running edlin or a DOS grep, etc), then
             // this will return a short file name.
@@ -390,7 +327,7 @@ namespace System.IO
         public override DateTimeOffset GetCreationTime(string fullPath)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, false);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: false);
             if (errorCode != 0)
                 throw Win32Marshal.GetExceptionForWin32Error(errorCode, fullPath);
 
@@ -408,7 +345,7 @@ namespace System.IO
         public override DateTimeOffset GetLastAccessTime(string fullPath)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, false);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: false);
             if (errorCode != 0)
                 throw Win32Marshal.GetExceptionForWin32Error(errorCode, fullPath);
 
@@ -419,7 +356,7 @@ namespace System.IO
         public override DateTimeOffset GetLastWriteTime(string fullPath)
         {
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, false);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: false);
             if (errorCode != 0)
                 throw Win32Marshal.GetExceptionForWin32Error(errorCode, fullPath);
 
@@ -452,15 +389,10 @@ namespace System.IO
             }
         }
 
-        public override FileStream Open(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent)
-        {
-            return new FileStream(fullPath, mode, access, share, bufferSize, options);
-        }
-
         [System.Security.SecurityCritical]
         private static SafeFileHandle OpenHandle(string fullPath, bool asDirectory)
         {
-            String root = fullPath.Substring(0, PathInternal.GetRootLength(fullPath));
+            string root = fullPath.Substring(0, PathInternal.GetRootLength(fullPath));
             if (root == fullPath && root[1] == Path.VolumeSeparatorChar)
             {
                 // intentionally not fullpath, most upstack public APIs expose this as path.
@@ -470,11 +402,11 @@ namespace System.IO
             Interop.Kernel32.SECURITY_ATTRIBUTES secAttrs = default(Interop.Kernel32.SECURITY_ATTRIBUTES);
             SafeFileHandle handle = Interop.Kernel32.SafeCreateFile(
                 fullPath,
-                (int)Interop.Kernel32.GenericOperations.GENERIC_WRITE,
+                Interop.Kernel32.GenericOperations.GENERIC_WRITE,
                 FileShare.ReadWrite | FileShare.Delete,
                 ref secAttrs,
                 FileMode.Open,
-                asDirectory ? (int)Interop.Kernel32.FileOperations.FILE_FLAG_BACKUP_SEMANTICS : (int)FileOptions.None,
+                asDirectory ? Interop.Kernel32.FileOperations.FILE_FLAG_BACKUP_SEMANTICS : (int)FileOptions.None,
                 IntPtr.Zero
             );
 
@@ -499,7 +431,7 @@ namespace System.IO
             // but for now we're much safer if we err on the conservative side.
             // This applies to symbolic links and mount points.
             Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA data = new Interop.Kernel32.WIN32_FILE_ATTRIBUTE_DATA();
-            int errorCode = FillAttributeInfo(fullPath, ref data, false, true);
+            int errorCode = FillAttributeInfo(fullPath, ref data, returnErrorOnNotFound: true);
             if (errorCode != 0)
             {
                 // Ensure we throw a DirectoryNotFoundException.
@@ -528,7 +460,7 @@ namespace System.IO
             // but for now we're much safer if we err on the conservative side.
             // This applies to symbolic links and mount points.
             // Note the logic to check whether fullPath is a reparse point is
-            // in Delete(String, String, bool), and will set "recursive" to false.
+            // in Delete(string, string, bool), and will set "recursive" to false.
             // Note that Win32's DeleteFile and RemoveDirectory will just delete
             // the reparse point itself.
 
@@ -576,7 +508,7 @@ namespace System.IO
                                 if (data.dwReserved0 == Interop.Kernel32.IOReparseOptions.IO_REPARSE_TAG_MOUNT_POINT)
                                 {
                                     // Use full path plus a trailing '\'
-                                    String mountPoint = Path.Combine(fullPath, data.cFileName + PathHelpers.DirectorySeparatorCharAsString);
+                                    string mountPoint = Path.Combine(fullPath, data.cFileName + PathHelpers.DirectorySeparatorCharAsString);
                                     if (!Interop.Kernel32.DeleteVolumeMountPoint(mountPoint))
                                     {
                                          errorCode = Marshal.GetLastWin32Error();
@@ -599,7 +531,7 @@ namespace System.IO
 
                                 // RemoveDirectory on a symbolic link will
                                 // remove the link itself.
-                                String reparsePoint = Path.Combine(fullPath, data.cFileName);
+                                string reparsePoint = Path.Combine(fullPath, data.cFileName);
                                 r = Interop.Kernel32.RemoveDirectory(reparsePoint);
                                 if (!r)
                                 {
@@ -621,7 +553,7 @@ namespace System.IO
                         }
                         else
                         {
-                            String fileName = Path.Combine(fullPath, data.cFileName);
+                            string fileName = Path.Combine(fullPath, data.cFileName);
                             r = Interop.Kernel32.DeleteFile(fileName);
                             if (!r)
                             {
diff --git a/src/System.IO.FileSystem/src/System/IO/Win32FileSystemEnumerable.cs b/src/System.IO.FileSystem/src/System/IO/Win32FileSystemEnumerable.cs
index 5d305718f8..cc1d3daf6d 100644
--- a/src/System.IO.FileSystem/src/System/IO/Win32FileSystemEnumerable.cs
+++ b/src/System.IO.FileSystem/src/System/IO/Win32FileSystemEnumerable.cs
@@ -2,13 +2,12 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using Microsoft.Win32.SafeHandles;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
 using System.Security;
 
-using Microsoft.Win32.SafeHandles;
-
 namespace System.IO
 {
     // Overview:
@@ -111,8 +110,6 @@ namespace System.IO
         private readonly SearchOption _searchOption;
         private readonly string _fullPath;
         private readonly string _normalizedSearchPath;
-        private readonly uint _oldMode;
-        private readonly bool _setBackOldMode;
 
         [SecuritySafeCritical]
         internal Win32FileSystemEnumerableIterator(string path, string originalUserPath, string searchPattern, SearchOption searchOption, SearchResultHandler<TSource> resultHandler)
@@ -123,8 +120,6 @@ namespace System.IO
             Debug.Assert(searchOption == SearchOption.AllDirectories || searchOption == SearchOption.TopDirectoryOnly);
             Debug.Assert(resultHandler != null);
 
-            _setBackOldMode = Interop.Kernel32.SetThreadErrorMode(Interop.Kernel32.SEM_FAILCRITICALERRORS, out _oldMode);
-
             string normalizedSearchPattern = PathHelpers.NormalizeSearchPattern(searchPattern);
 
             if (normalizedSearchPattern.Length == 0)
@@ -166,27 +161,31 @@ namespace System.IO
 
             Interop.Kernel32.WIN32_FIND_DATA data = new Interop.Kernel32.WIN32_FIND_DATA();
 
-            // Open a Find handle
-            _hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
-
-            if (_hnd.IsInvalid)
+            using (new DisableMediaInsertionPrompt())
             {
-                int errorCode = Marshal.GetLastWin32Error();
-                if (errorCode != Interop.Errors.ERROR_FILE_NOT_FOUND && errorCode != Interop.Errors.ERROR_NO_MORE_FILES)
-                {
-                    HandleError(errorCode, _searchData.FullPath);
-                }
-                else
+                // Open a Find handle
+                _hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
+
+                if (_hnd.IsInvalid)
                 {
-                    // flag this as empty only if we're searching just top directory
-                    // Used in fast path for top directory only
-                    _empty = _searchOption == SearchOption.TopDirectoryOnly;
+                    int errorCode = Marshal.GetLastWin32Error();
+                    if (errorCode != Interop.Errors.ERROR_FILE_NOT_FOUND && errorCode != Interop.Errors.ERROR_NO_MORE_FILES)
+                    {
+                        throw HandleError(errorCode, _searchData.FullPath);
+                    }
+                    else
+                    {
+                        // flag this as empty only if we're searching just top directory
+                        // Used in fast path for top directory only
+                        _empty = _searchOption == SearchOption.TopDirectoryOnly;
+                    }
                 }
             }
-            // fast path for TopDirectoryOnly. If we have a result, go ahead and set it to
-            // current. If empty, dispose handle.
+
             if (_searchOption == SearchOption.TopDirectoryOnly)
             {
+                // fast path for TopDirectoryOnly. If we have a result, go ahead and set it to
+                // current. If empty, dispose handle.
                 if (_empty)
                 {
                     _hnd.Dispose();
@@ -200,10 +199,10 @@ namespace System.IO
                     }
                 }
             }
-            // for AllDirectories, we first recurse into dirs, so cleanup and add searchData
-            // to the list
             else
             {
+                // for AllDirectories, we first recurse into dirs, so cleanup and add searchData
+                // to the list
                 _hnd.Dispose();
                 _searchList = new List<PathPair>();
                 _searchList.Add(_searchData);
@@ -245,18 +244,10 @@ namespace System.IO
         {
             try
             {
-                if (_hnd != null)
-                {
-                    _hnd.Dispose();
-                }
+                _hnd?.Dispose();
             }
             finally
             {
-                if (_setBackOldMode)
-                {
-                    uint _ignore;
-                    Interop.Kernel32.SetThreadErrorMode(_oldMode, out _ignore);
-                }
                 base.Dispose(disposing);
             }
         }
@@ -310,16 +301,25 @@ namespace System.IO
                             // Execute searchCriteria against the current directory
                             string searchPath = Path.Combine(_searchData.FullPath, _searchCriteria);
 
-                            // Open a Find handle
-                            _hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
-                            if (_hnd.IsInvalid)
+                            using (new DisableMediaInsertionPrompt())
                             {
-                                int errorCode = Marshal.GetLastWin32Error();
-                                if (errorCode == Interop.Errors.ERROR_FILE_NOT_FOUND || errorCode == Interop.Errors.ERROR_NO_MORE_FILES || errorCode == Interop.Errors.ERROR_PATH_NOT_FOUND)
-                                    continue;
+                                // Open a Find handle
+                                _hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
 
-                                _hnd.Dispose();
-                                HandleError(errorCode, _searchData.FullPath);
+                                if (_hnd.IsInvalid)
+                                {
+                                    int errorCode = Marshal.GetLastWin32Error();
+                                    switch (errorCode)
+                                    {
+                                        case Interop.Errors.ERROR_FILE_NOT_FOUND:
+                                        case Interop.Errors.ERROR_NO_MORE_FILES:
+                                        case Interop.Errors.ERROR_PATH_NOT_FOUND:
+                                            continue;
+                                    }
+
+                                    _hnd.Dispose();
+                                    throw HandleError(errorCode, _searchData.FullPath);
+                                }
                             }
 
                             state = STATE_FIND_NEXT_FILE;
@@ -342,32 +342,39 @@ namespace System.IO
                     {
                         if (_hnd != null)
                         {
-                            // Keep asking for more matching files/dirs, add it to the list
-                            while (Interop.Kernel32.FindNextFile(_hnd, ref data))
+                            using (new DisableMediaInsertionPrompt())
                             {
-                                TSource result;
-                                if (IsResultIncluded(ref data, out result))
+                                // Keep asking for more matching files/dirs, add it to the list
+                                while (Interop.Kernel32.FindNextFile(_hnd, ref data))
                                 {
-                                    current = result;
-                                    return true;
+                                    TSource result;
+                                    if (IsResultIncluded(ref data, out result))
+                                    {
+                                        current = result;
+                                        return true;
+                                    }
                                 }
                             }
 
                             // Make sure we quit with a sensible error.
                             int errorCode = Marshal.GetLastWin32Error();
+                            _hnd?.Dispose();
 
-                            if (_hnd != null)
-                                _hnd.Dispose();
-
-                            // ERROR_FILE_NOT_FOUND is valid here because if the top level
-                            // dir doesn't contain any subdirs and matching files then
-                            // we will get here with this errorcode from the _searchList walk
-                            if ((errorCode != 0) && (errorCode != Interop.Errors.ERROR_NO_MORE_FILES)
-                                && (errorCode != Interop.Errors.ERROR_FILE_NOT_FOUND))
+                            switch (errorCode)
                             {
-                                HandleError(errorCode, _searchData.FullPath);
+                                case Interop.Errors.ERROR_SUCCESS:
+                                case Interop.Errors.ERROR_NO_MORE_FILES:
+
+                                // ERROR_FILE_NOT_FOUND is valid here because if the top level
+                                // dir doesn't contain any subdirs and matching files then
+                                // we will get here with this errorcode from the _searchList walk
+                                case Interop.Errors.ERROR_FILE_NOT_FOUND:
+                                    break;
+                                default:
+                                    throw HandleError(errorCode, _searchData.FullPath);
                             }
                         }
+
                         if (_searchOption == SearchOption.TopDirectoryOnly)
                         {
                             state = STATE_FINISH;
@@ -398,10 +405,10 @@ namespace System.IO
         }
 
         [SecurityCritical]
-        private void HandleError(int errorCode, string path)
+        private Exception HandleError(int errorCode, string path)
         {
             Dispose();
-            throw Win32Marshal.GetExceptionForWin32Error(errorCode, path);
+            return Win32Marshal.GetExceptionForWin32Error(errorCode, path);
         }
 
         [SecurityCritical]  // auto-generated
@@ -412,20 +419,28 @@ namespace System.IO
             Interop.Kernel32.WIN32_FIND_DATA data = new Interop.Kernel32.WIN32_FIND_DATA();
             try
             {
-                // Get all files and dirs
-                hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
-
-                if (hnd.IsInvalid)
+                using (new DisableMediaInsertionPrompt())
                 {
-                    int errorCode = Marshal.GetLastWin32Error();
+                    // Get all files and dirs
+                    hnd = Interop.Kernel32.FindFirstFile(searchPath, ref data);
 
-                    // This could happen if the dir doesn't contain any files.
-                    // Continue with the recursive search though, eventually
-                    // _searchList will become empty
-                    if (errorCode == Interop.Errors.ERROR_FILE_NOT_FOUND || errorCode == Interop.Errors.ERROR_NO_MORE_FILES || errorCode == Interop.Errors.ERROR_PATH_NOT_FOUND)
-                        return;
+                    if (hnd.IsInvalid)
+                    {
+                        int errorCode = Marshal.GetLastWin32Error();
 
-                    HandleError(errorCode, localSearchData.FullPath);
+                        // This could happen if the dir doesn't contain any files.
+                        // Continue with the recursive search though, eventually
+                        // _searchList will become empty
+                        switch (errorCode)
+                        {
+                            case Interop.Errors.ERROR_FILE_NOT_FOUND:
+                            case Interop.Errors.ERROR_NO_MORE_FILES:
+                            case Interop.Errors.ERROR_PATH_NOT_FOUND:
+                                return;
+                            default:
+                                throw HandleError(errorCode, localSearchData.FullPath);
+                        }
+                    }
                 }
 
                 // Add subdirs to _searchList. Exempt ReparsePoints as appropriate
@@ -458,8 +473,7 @@ namespace System.IO
             }
             finally
             {
-                if (hnd != null)
-                    hnd.Dispose();
+                hnd?.Dispose();
             }
         }
 
diff --git a/src/System.IO.FileSystem/src/System/IO/WinRTFileStream.cs b/src/System.IO.FileSystem/src/System/IO/WinRTFileStream.cs
deleted file mode 100644
index 3f83fa0e64..0000000000
--- a/src/System.IO.FileSystem/src/System/IO/WinRTFileStream.cs
+++ /dev/null
@@ -1,245 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using Microsoft.Win32.SafeHandles;
-using System.Diagnostics;
-using System.Threading;
-using System.Threading.Tasks;
-using Windows.Storage;
-
-namespace System.IO
-{
-    internal sealed class WinRTFileStream : FileStreamBase
-    {
-        private readonly FileAccess _access;
-        private bool _disposed;
-        private StorageFile _file;
-        private readonly Stream _innerStream;
-        private readonly FileOptions _options;
-        private static readonly SafeFileHandle s_invalidHandle = new SafeFileHandle(IntPtr.Zero, false);
-
-        internal WinRTFileStream(Stream innerStream, StorageFile file, FileAccess access, FileOptions options, FileStream parent) 
-            : base(parent)
-        {
-            Debug.Assert(innerStream != null);
-            Debug.Assert(file != null);
-
-            this._access = access;
-            this._disposed = false;
-            this._file = file;
-            this._innerStream = innerStream;
-            this._options = options;
-        }
-
-        ~WinRTFileStream()
-        {
-            Dispose(false);
-        }
-
-        #region FileStream members
-        public override bool IsAsync { get { return true; } }
-        public override string Name { get { return _file.Name; } }
-        public override Microsoft.Win32.SafeHandles.SafeFileHandle SafeFileHandle { get { return s_invalidHandle; } }
-        internal override bool IsClosed => false;
-
-        public override void Flush(bool flushToDisk)
-        {
-            // WinRT streams are not buffered, however the WinRT stream will be wrapped in a BufferedStream
-            // Flush & FlushAsync will flush the internal managed buffer of the BufferedStream wrapper
-            // The WinRT stream only exposes FlushAsync which flushes to disk.
-            // The managed Stream adapter does nothing for Flush() and forwards to WinRT for FlushAsync (flushing to disk).
-            if (flushToDisk)
-            {
-                // FlushAsync() will do the write to disk when it hits the WinRT->NetFx adapter
-                Task flushTask = _innerStream.FlushAsync();
-                flushTask.Wait();
-            }
-            else
-            {
-                // Flush doesn't write to disk
-                _innerStream.Flush();
-            }
-        }
-
-        public override void Lock(long position, long length)
-        {
-            throw new PlatformNotSupportedException(); // https://github.com/dotnet/corefx/issues/17470
-        }
-
-        public override void Unlock(long position, long length)
-        {
-            throw new PlatformNotSupportedException(); // https://github.com/dotnet/corefx/issues/17470
-        }
-        #endregion
-
-        #region Stream members
-        #region Properties
-
-        public override bool CanRead
-        {
-            // WinRT doesn't support write-only streams, override what the stream tells us 
-            // with what was passed in when creating it.
-            get { return _innerStream.CanRead && (_access & FileAccess.Read) != 0; }
-        }
-
-        public override bool CanSeek
-        {
-            get { return _innerStream.CanSeek; }
-        }
-
-        public override bool CanWrite
-        {
-            get { return _innerStream.CanWrite; }
-        }
-
-        public override long Length
-        {
-            get { return _innerStream.Length; }
-        }
-
-        public override long Position
-        {
-            get { return _innerStream.Position; }
-            set { _innerStream.Position = value; }
-        }
-
-        public override int ReadTimeout
-        {
-            get { return _innerStream.ReadTimeout; }
-            set { _innerStream.ReadTimeout = value; }
-        }
-
-        public override bool CanTimeout
-        {
-            get { return _innerStream.CanTimeout; }
-        }
-
-        public override int WriteTimeout
-        {
-            get { return _innerStream.WriteTimeout; }
-            set { _innerStream.WriteTimeout = value; }
-        }
-
-        #endregion Properties
-
-        #region Methods
-        public override Task CopyToAsync(Stream destination, int bufferSize, CancellationToken cancellationToken)
-        {
-            return _innerStream.CopyToAsync(destination, bufferSize, cancellationToken);
-        }
-
-        protected override void Dispose(bool disposing)
-        {
-            try
-            {
-                if (disposing)
-                    _innerStream.Dispose();
-
-                if ((_options & FileOptions.DeleteOnClose) != 0 && _file != null)
-                {
-                    // WinRT doesn't directly support DeleteOnClose but we can mimic it
-                    // There are a few reasons that this will fail
-                    //   1) the file may not allow delete permissions for the current user
-                    //   2) the storage file RCW may have already been disconnected
-                    try
-                    {
-                        _file.DeleteAsync().AsTask().Wait();
-                    }
-                    catch { }
-                }
-
-                _disposed = true;
-                _file = null;
-            }
-            finally
-            {
-                base.Dispose(disposing);
-            }
-        }
-
-        public override void Flush()
-        {
-            _parent.Flush(false);
-        }
-
-        public override Task FlushAsync(CancellationToken cancellationToken)
-        {
-            return _innerStream.FlushAsync(cancellationToken);
-        }
-
-        public override int Read(byte[] buffer, int offset, int count)
-        {
-            if (!_disposed && !CanRead)
-                throw Error.GetReadNotSupported();
-
-            return _innerStream.Read(buffer, offset, count);
-        }
-
-        public override Task<int> ReadAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            if (!_disposed && !CanRead)
-                throw Error.GetReadNotSupported();
-
-            return _innerStream.ReadAsync(buffer, offset, count, cancellationToken);
-        }
-
-        public override int ReadByte()
-        {
-            if (!_disposed && !CanRead)
-                throw Error.GetReadNotSupported();
-
-            return _innerStream.ReadByte();
-        }
-
-        public override long Seek(long offset, SeekOrigin origin)
-        {
-            if (origin == SeekOrigin.Begin && offset < 0)
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_NEGATIVE_SEEK);
-
-            return _innerStream.Seek(offset, origin);
-        }
-
-        public override void SetLength(long value)
-        {
-            _innerStream.SetLength(value);
-
-            // WinRT ignores all errors when setting length, check after setting
-
-            if (_innerStream.Length < value)
-            {
-                throw new ArgumentOutOfRangeException(nameof(value), SR.ArgumentOutOfRange_FileLengthTooBig);
-            }
-            else if (_innerStream.Length != value)
-            {
-                throw new ArgumentException(SR.Argument_FileNotResized, nameof(value));
-            }
-
-            // WinRT doesn't update the position when truncating a file
-            if (value < _innerStream.Position)
-                _innerStream.Position = value;
-        }
-
-        public override string ToString()
-        {
-            return _innerStream.ToString();
-        }
-
-        public override void Write(byte[] buffer, int offset, int count)
-        {
-            _innerStream.Write(buffer, offset, count);
-        }
-
-        public override Task WriteAsync(byte[] buffer, int offset, int count, CancellationToken cancellationToken)
-        {
-            return _innerStream.WriteAsync(buffer, offset, count, cancellationToken);
-        }
-
-        public override void WriteByte(byte value)
-        {
-            _innerStream.WriteByte(value);
-        }
-        #endregion Methods
-        #endregion Stream members
-    }
-}
diff --git a/src/System.IO.FileSystem/src/System/IO/WinRTFileSystem.cs b/src/System.IO.FileSystem/src/System/IO/WinRTFileSystem.cs
index 1ddc7f834e..9d838d605c 100644
--- a/src/System.IO.FileSystem/src/System/IO/WinRTFileSystem.cs
+++ b/src/System.IO.FileSystem/src/System/IO/WinRTFileSystem.cs
@@ -19,65 +19,6 @@ namespace System.IO
 {
     internal sealed partial class WinRTFileSystem : FileSystem
     {
-        public override int MaxPath { get { return Interop.Kernel32.MAX_PATH; } }
-        public override int MaxDirectoryPath { get { return Interop.Kernel32.MAX_DIRECTORY_PATH; } }
-
-        private static System.IO.FileAttributes ConvertFileAttributes(WinRTFileAttributes fileAttributes)
-        {
-            //namespace Windows.Storage
-            //{
-            //    [Flags]
-            //    public enum FileAttributes
-            //    {
-            //        Normal = 0,
-            //        ReadOnly = 1,
-            //        Directory = 16,
-            //        Archive = 32,
-            //        Temporary = 256,
-            //        LocallyIncomplete = 512,
-            //    }
-            //}
-
-            //namespace System.IO
-            //{
-            //    [Flags]
-            //    public enum FileAttributes
-            //    {
-            //        ReadOnly = 1,
-            //        Hidden = 2,
-            //        System = 4,
-            //        Directory = 16,
-            //        Archive = 32,
-            //        Device = 64,
-            //        Normal = 128,
-            //        Temporary = 256,
-            //        SparseFile = 512,
-            //        ReparsePoint = 1024,
-            //        Compressed = 2048,
-            //        Offline = 4096,
-            //        NotContentIndexed = 8192,
-            //        Encrypted = 16384,
-            //    }
-            //}
-
-            // Normal is a special case and happens to have different values in WinRT and Win32.
-            // It's meant to indicate the absence of other flags.  On WinRT this logically is 0,
-            // however on Win32 it is represented with a discrete value of 128.
-            return (fileAttributes == WinRTFileAttributes.Normal) ?
-                FileAttributes.Normal :
-                (FileAttributes)fileAttributes;
-        }
-
-        private static WinRTFileAttributes ConvertFileAttributes(FileAttributes fileAttributes)
-        {
-            // see comment above
-            // Here we make sure to remove the "normal" value since it is redundant
-            // We do not mask unsupported values 
-            return (fileAttributes == FileAttributes.Normal) ?
-                WinRTFileAttributes.Normal :
-                (WinRTFileAttributes)(fileAttributes & ~FileAttributes.Normal);
-        }
-
         public override void CopyFile(string sourceFullPath, string destFullPath, bool overwrite)
         {
             EnsureBackgroundThread();
@@ -117,391 +58,11 @@ namespace System.IO
             await DeleteFileAsync(sourceFullPath).ConfigureAwait(false);
         }
 
-        public override void CreateDirectory(string fullPath)
-        {
-            EnsureBackgroundThread();
-            SynchronousResultOf(CreateDirectoryAsync(fullPath, failIfExists: false));
-        }
-
-        private async Task<StorageFolder> CreateDirectoryAsync(string fullPath, bool failIfExists)
-        {
-            if (fullPath.Length >= Interop.Kernel32.MAX_DIRECTORY_PATH)
-                throw new PathTooLongException(SR.IO_PathTooLong);
-
-            Stack<string> stackDir = new Stack<string>();
-            StorageFolder workingFolder = null;
-            string workingPath = fullPath;
-
-            // walk up the path until we can get a directory
-            while (workingFolder == null)
-            {
-                try
-                {
-                    workingFolder = await StorageFolder.GetFolderFromPathAsync(workingPath).TranslateWinRTTask(workingPath, isDirectory: true);
-                }
-                catch (IOException) { }
-                catch (UnauthorizedAccessException) { }
-
-                if (workingFolder == null)
-                {
-                    // we couldn't get the directory, we'll need to create it
-                    string folderName = null;
-                    PathHelpers.SplitDirectoryFile(workingPath, out workingPath, out folderName);
-
-                    if (String.IsNullOrEmpty(folderName))
-                    {
-                        // we reached the root and it did not exist.  we can't create roots.
-                        throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_PATH_NOT_FOUND, workingPath);
-                    }
-
-                    stackDir.Push(folderName);
-                    Debug.Assert(!String.IsNullOrEmpty(workingPath));
-                }
-            }
-
-            Debug.Assert(workingFolder != null);
-
-            if (failIfExists && (stackDir.Count == 0))
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_ALREADY_EXISTS, fullPath);
-
-            // we have work to do.  if stackDir is empty it means we were passed a path to an existing directory.
-            while (stackDir.Count > 0)
-            {
-                // use CreationCollisionOption.OpenIfExists to address a race conditions when creating directories
-                workingFolder = await workingFolder.CreateFolderAsync(stackDir.Pop(), CreationCollisionOption.OpenIfExists).TranslateWinRTTask(fullPath, isDirectory: true);
-            }
-
-            return workingFolder;
-        }
-
-        public override void DeleteFile(string fullPath)
-        {
-            EnsureBackgroundThread();
-            SynchronousResultOf(DeleteFileAsync(fullPath));
-        }
-
-        private async Task DeleteFileAsync(string fullPath)
-        {
-            try
-            {
-                // Note the absence of TranslateWinRTTask, we translate below in the catch block.
-                StorageFile file = await StorageFile.GetFileFromPathAsync(fullPath).AsTask().ConfigureAwait(false);
-                await file.DeleteAsync(StorageDeleteOption.PermanentDelete).AsTask().ConfigureAwait(false);
-            }
-            catch (Exception exception)
-            {
-                // For consistency with Win32 we ignore missing files
-                if (exception.HResult != HResults.ERROR_FILE_NOT_FOUND)
-                    throw exception.TranslateWinRTException(fullPath);
-            }
-        }
-
-        public override bool DirectoryExists(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(DirectoryExistsAsync(fullPath));
-        }
-
-        private async Task<bool> DirectoryExistsAsync(string fullPath)
-        {
-            string directoryPath = null, fileName = null;
-            PathHelpers.SplitDirectoryFile(fullPath, out directoryPath, out fileName);
-
-            // Rather than call await StorageFolder.GetFolderFromPathAsync(fullPath); and catch FileNotFoundException
-            // we try to avoid the exception by calling TryGetItemAsync.
-            // We can still hit an exception if the parent directory doesn't exist but it does provide better performance
-            // for the existing parent/non-existing directory case and avoids a first chance exception which is a developer
-            // pain point.
-
-            StorageFolder parent = null;
-            try
-            {
-                parent = await StorageFolder.GetFolderFromPathAsync(directoryPath).TranslateWinRTTask(directoryPath, isDirectory: true);
-            }
-            catch (IOException) { }
-            catch (UnauthorizedAccessException) { }
-
-            if (String.IsNullOrEmpty(fileName))
-            {
-                // we were given a root
-                return parent != null;
-            }
-
-            if (parent != null)
-            {
-                StorageFolder folder = await parent.TryGetItemAsync(fileName).TranslateWinRTTask(fullPath, isDirectory: true) as StorageFolder;
-                return folder != null;
-            }
-            else
-            {
-                // it's possible we don't have access to the parent but do have access to this folder
-                try
-                {
-                    StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(fullPath).TranslateWinRTTask(fullPath, isDirectory: true);
-                    return folder != null;
-                }
-                catch (IOException) { }
-                catch (UnauthorizedAccessException) { }
-            }
-
-            return false;
-        }
-
-
-        public override IEnumerable<string> EnumeratePaths(string fullPath, string searchPattern, SearchOption searchOption, SearchTarget searchTarget)
-        {
-            IReadOnlyList<IStorageItem> storageFiles = SynchronousResultOf(EnumerateFileQuery(fullPath, searchPattern, searchOption, searchTarget));
-            return IteratePathsFromStorageItems(storageFiles);
-        }
-
-        public override IEnumerable<FileSystemInfo> EnumerateFileSystemInfos(string fullPath, string searchPattern, SearchOption searchOption, SearchTarget searchTarget)
-        {
-            IReadOnlyList<IStorageItem> storageFiles = SynchronousResultOf(EnumerateFileQuery(fullPath, searchPattern, searchOption, searchTarget));
-            return IterateFileSystemInfosFromStorageItems(storageFiles);
-        }
-
-        /// <summary>
-        /// Translates IStorageItems into FileSystemInfos and yields the results.
-        /// </summary>
-        private static IEnumerable<FileSystemInfo> IterateFileSystemInfosFromStorageItems(IReadOnlyList<IStorageItem> storageFiles)
-        {
-            int count = storageFiles.Count;
-            for (int i = 0; i < count; i++)
-            {
-                if (storageFiles[i].IsOfType(StorageItemTypes.Folder))
-                {
-                    yield return new DirectoryInfo(storageFiles[i].Path);
-                }
-                else // If it is neither a File nor folder then we treat it as a File.
-                {
-                    yield return new FileInfo(storageFiles[i].Path);
-                }
-            }
-        }
-
-        /// <summary>
-        /// Translates IStorageItems into string paths and yields the results.
-        /// </summary>
-        private static IEnumerable<string> IteratePathsFromStorageItems(IReadOnlyList<IStorageItem> storageFiles)
-        {
-            int count = storageFiles.Count;
-            for (int i = 0; i < count; i++)
-            {
-                yield return storageFiles[i].Path;
-            }
-        }
-
-        private async static Task<IReadOnlyList<IStorageItem>> EnumerateFileQuery(string path, string searchPattern, SearchOption searchOption, SearchTarget searchTarget)
-        {
-            // Get a StorageFolder for "path"
-            string fullPath = Path.GetFullPath(path);
-            StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(fullPath).TranslateWinRTTask(fullPath, isDirectory: true);
-
-            // Construct a query for the search.
-            QueryOptions query = new QueryOptions();
-
-            // Translate SearchOption into FolderDepth
-            query.FolderDepth = searchOption == SearchOption.AllDirectories ? FolderDepth.Deep : FolderDepth.Shallow;
-
-            // Construct an AQS filter
-            string normalizedSearchPattern = PathHelpers.NormalizeSearchPattern(searchPattern);
-            if (normalizedSearchPattern.Length == 0)
-            {
-                // An empty searchPattern will return no results and requires no AQS parsing.
-                return new IStorageItem[0];
-            }
-            else
-            {
-                // Parse the query as an ItemPathDisplay filter.
-                string searchPath = PathHelpers.GetFullSearchString(fullPath, normalizedSearchPattern);
-                string aqs = "System.ItemPathDisplay:~\"" + searchPath + "\"";
-                query.ApplicationSearchFilter = aqs;
-
-                // If the filtered path is deeper than the given user path, we need to get a new folder for it.
-                // This occurs when someone does something like Enumerate("C:\first\second\", "C:\first\second\third\*").
-                // When AllDirectories is set this isn't an issue, but for TopDirectoryOnly we have to do some special work
-                // to make sure something is actually returned when the searchPattern is a subdirectory of the path.
-                // To do this, we attempt to get a new StorageFolder for the subdirectory and return an empty enumerable
-                // if we can't.
-                string searchPatternDirName = Path.GetDirectoryName(normalizedSearchPattern);
-                string userPath = string.IsNullOrEmpty(searchPatternDirName) ? fullPath : Path.Combine(fullPath, searchPatternDirName);
-                if (userPath != folder.Path)
-                {
-                    folder = await StorageFolder.GetFolderFromPathAsync(userPath).TranslateWinRTTask(userPath, isDirectory: true);
-                }
-            }
-
-            // Execute our built query
-            if (searchTarget == SearchTarget.Files)
-            {
-                StorageFileQueryResult queryResult = folder.CreateFileQueryWithOptions(query);
-                return await queryResult.GetFilesAsync().TranslateWinRTTask(folder.Path, isDirectory: true);
-            }
-            else if (searchTarget == SearchTarget.Directories)
-            {
-                StorageFolderQueryResult queryResult = folder.CreateFolderQueryWithOptions(query);
-                return await queryResult.GetFoldersAsync().TranslateWinRTTask(folder.Path, isDirectory: true);
-            }
-            else
-            {
-                StorageItemQueryResult queryResult = folder.CreateItemQueryWithOptions(query);
-                return await queryResult.GetItemsAsync().TranslateWinRTTask(folder.Path, isDirectory: true);
-            }
-        }
-
-        public override bool FileExists(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(FileExistsAsync(fullPath));
-        }
-
-        private async Task<bool> FileExistsAsync(string fullPath)
-        {
-            string directoryPath = null, fileName = null;
-            PathHelpers.SplitDirectoryFile(fullPath, out directoryPath, out fileName);
-
-            if (String.IsNullOrEmpty(fileName))
-            {
-                // No filename was provided
-                return false;
-            }
-
-            // Rather than call await StorageFile.GetFileFromPathAsync(fullPath); and catch FileNotFoundException
-            // we try to avoid the exception by calling TryGetItemAsync.
-            // We can still hit an exception if the directory doesn't exist but it does provide better performance
-            // for the existing folder/non-existing file case and avoids a first chance exception which is a developer
-            // pain point.
-
-            StorageFolder parent = null;
-            try
-            {
-                parent = await StorageFolder.GetFolderFromPathAsync(directoryPath).TranslateWinRTTask(directoryPath);
-            }
-            catch (IOException) { }
-            catch (UnauthorizedAccessException) { }
-
-            StorageFile file = null;
-
-            if (parent != null)
-            {
-                // The expectation is that this API will never throw, thus it is missing TranslateWinRTTask
-                file = await parent.TryGetItemAsync(fileName).TranslateWinRTTask(fullPath) as StorageFile;
-            }
-            else
-            {
-                // it's possible we don't have access to the parent but do have access to this file
-                try
-                {
-                    file = await StorageFile.GetFileFromPathAsync(fullPath).TranslateWinRTTask(fullPath);
-                }
-                catch (IOException) { }
-                catch (UnauthorizedAccessException) { }
-            }
-
-            return (file != null) ? file.IsAvailable : false;
-        }
-
-        public override FileAttributes GetAttributes(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(GetAttributesAsync(fullPath));
-        }
-
-        private async Task<FileAttributes> GetAttributesAsync(string fullPath)
-        {
-            IStorageItem item = await GetStorageItemAsync(fullPath).ConfigureAwait(false);
-
-            return ConvertFileAttributes(item.Attributes);
-        }
-
-        public override DateTimeOffset GetCreationTime(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(GetCreationTimeAsync(fullPath));
-        }
-
-        private async Task<DateTimeOffset> GetCreationTimeAsync(string fullPath)
-        {
-            IStorageItem item = await GetStorageItemAsync(fullPath).ConfigureAwait(false);
-
-            return item.DateCreated;
-        }
-
         public override string GetCurrentDirectory()
         {
             throw new PlatformNotSupportedException(); // https://github.com/dotnet/corefx/issues/17470;
         }
 
-        public override IFileSystemObject GetFileSystemInfo(string fullPath, bool asDirectory)
-        {
-            return new WinRTFileSystemObject(fullPath, asDirectory);
-        }
-
-        public override DateTimeOffset GetLastAccessTime(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(GetLastAccessTimeAsync(fullPath));
-        }
-
-        private async Task<DateTimeOffset> GetLastAccessTimeAsync(string fullPath)
-        {
-            IStorageItem item = await GetStorageItemAsync(fullPath).ConfigureAwait(false);
-
-            return await GetLastAccessTimeAsync(item).ConfigureAwait(false);
-        }
-
-        // declare a static to avoid unnecessary heap allocations
-        private static readonly string[] s_dateAccessedKey = { "System.DateAccessed" };
-
-        private static async Task<DateTimeOffset> GetLastAccessTimeAsync(IStorageItem item)
-        {
-            BasicProperties properties = await item.GetBasicPropertiesAsync().TranslateWinRTTask(item.Path);
-
-            var propertyMap = await properties.RetrievePropertiesAsync(s_dateAccessedKey).TranslateWinRTTask(item.Path);
-
-            // shell doesn't expose this metadata on all item types
-            if (propertyMap.ContainsKey(s_dateAccessedKey[0]))
-            {
-                return (DateTimeOffset)propertyMap[s_dateAccessedKey[0]];
-            }
-
-            // fallback to modified date
-            return properties.DateModified;
-        }
-
-        public override DateTimeOffset GetLastWriteTime(string fullPath)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(GetLastWriteTimeAsync(fullPath));
-        }
-
-        private async Task<DateTimeOffset> GetLastWriteTimeAsync(string fullPath)
-        {
-            IStorageItem item = await GetStorageItemAsync(fullPath).ConfigureAwait(false);
-
-            return await GetLastWriteTimeAsync(item).ConfigureAwait(false);
-        }
-
-        private static async Task<DateTimeOffset> GetLastWriteTimeAsync(IStorageItem item)
-        {
-            BasicProperties properties = await item.GetBasicPropertiesAsync().TranslateWinRTTask(item.Path);
-
-            return properties.DateModified;
-        }
-
-        private static async Task<IStorageItem> GetStorageItemAsync(string fullPath)
-        {
-            string directoryPath, itemName;
-            PathHelpers.SplitDirectoryFile(fullPath, out directoryPath, out itemName);
-
-            StorageFolder parent = await StorageFolder.GetFolderFromPathAsync(directoryPath).TranslateWinRTTask(directoryPath, isDirectory: true);
-
-            if (String.IsNullOrEmpty(itemName))
-                return parent;
-
-            return await parent.GetItemAsync(itemName).TranslateWinRTTask(fullPath);
-        }
-
         public override void MoveDirectory(string sourceFullPath, string destFullPath)
         {
             EnsureBackgroundThread();
@@ -519,10 +80,10 @@ namespace System.IO
             PathHelpers.SplitDirectoryFile(destFullPath, out destParent, out destFolderName);
 
             // same parent folder
-            if (String.Equals(sourceParent, destParent, StringComparison.OrdinalIgnoreCase))
+            if (string.Equals(sourceParent, destParent, StringComparison.OrdinalIgnoreCase))
             {
                 // not the same subfolder
-                if (!String.Equals(sourceFolderName, destFolderName, StringComparison.OrdinalIgnoreCase))
+                if (!string.Equals(sourceFolderName, destFolderName, StringComparison.OrdinalIgnoreCase))
                 {
                     await sourceFolder.RenameAsync(destFolderName).TranslateWinRTTask(destFullPath, isDirectory: true);
                 }
@@ -581,171 +142,11 @@ namespace System.IO
             }
         }
 
-        public override FileStreamBase Open(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent)
-        {
-            EnsureBackgroundThread();
-            return SynchronousResultOf(OpenAsync(fullPath, mode, access, share, bufferSize, options, parent));
-        }
-
-        private async Task<FileStreamBase> OpenAsync(string fullPath, FileMode mode, FileAccess access, FileShare share, int bufferSize, FileOptions options, FileStream parent)
-        {
-            // When trying to open the root directory, we need to throw an Access Denied
-            if (PathInternal.GetRootLength(fullPath) == fullPath.Length)
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_ACCESS_DENIED, fullPath);
-
-            // Win32 CreateFile returns ERROR_PATH_NOT_FOUND when given a path that ends with '\'
-            if (PathHelpers.EndsInDirectorySeparator(fullPath))
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_PATH_NOT_FOUND, fullPath);
-
-            StorageFile file = null;
-
-            // FileMode
-            if (mode == FileMode.Open || mode == FileMode.Truncate)
-            {
-                file = await StorageFile.GetFileFromPathAsync(fullPath).TranslateWinRTTask(fullPath);
-            }
-            else
-            {
-                CreationCollisionOption collisionOptions;
-
-                switch (mode)
-                {
-                    case FileMode.Create:
-                        collisionOptions = CreationCollisionOption.ReplaceExisting;
-                        break;
-                    case FileMode.CreateNew:
-                        collisionOptions = CreationCollisionOption.FailIfExists;
-                        break;
-                    case FileMode.Append:
-                    case FileMode.OpenOrCreate:
-                    default:
-                        collisionOptions = CreationCollisionOption.OpenIfExists;
-                        break;
-                }
-
-                string directoryPath, fileName;
-                PathHelpers.SplitDirectoryFile(fullPath, out directoryPath, out fileName);
-
-                StorageFolder directory = await StorageFolder.GetFolderFromPathAsync(directoryPath).TranslateWinRTTask(directoryPath, isDirectory: true);
-
-                file = await directory.CreateFileAsync(fileName, collisionOptions).TranslateWinRTTask(fullPath);
-            }
-
-            // FileAccess: WinRT doesn't support FileAccessMode.Write so we upgrade to ReadWrite
-            FileAccessMode accessMode = ((access & FileAccess.Write) != 0) ? FileAccessMode.ReadWrite : FileAccessMode.Read;
-
-            // FileShare: cannot translate StorageFile uses a different sharing model (oplocks) that is controlled via FileAccessMode
-
-            // FileOptions: ignore most values of FileOptions as they are hints and are not supported by WinRT.
-            // FileOptions.Encrypted is not a hint, and not supported by WinRT, but there is precedent for ignoring this (FAT).
-            // FileOptions.DeleteOnClose should result in an UnauthorizedAccessException when
-            //   opening a file that can only be read, but we cannot safely reproduce that behavior
-            //   in WinRT without actually deleting the file.  
-            //   Instead the failure will occur in the finalizer for WinRTFileStream and be ignored.
-
-            // open our stream
-            Stream stream = (await file.OpenAsync(accessMode).TranslateWinRTTask(fullPath)).AsStream(bufferSize);
-
-            if (mode == FileMode.Append)
-            {
-                // seek to end.
-                stream.Seek(0, SeekOrigin.End);
-            }
-            else if (mode == FileMode.Truncate)
-            {
-                // truncate stream to 0
-                stream.SetLength(0);
-            }
-
-            return new WinRTFileStream(stream, file, access, options, parent);
-        }
-
-        public override void RemoveDirectory(string fullPath, bool recursive)
-        {
-            EnsureBackgroundThread();
-            SynchronousResultOf(RemoveDirectoryAsync(fullPath, recursive));
-        }
-
-        private async Task RemoveDirectoryAsync(string fullPath, bool recursive)
-        {
-            StorageFolder folder = await StorageFolder.GetFolderFromPathAsync(fullPath).TranslateWinRTTask(fullPath, isDirectory: true);
-
-            // StorageFolder.DeleteAsync will always be recursive.  Detect a non-empty folder up front and throw.
-            if (!recursive && (await folder.GetItemsAsync()).Count != 0)
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_DIR_NOT_EMPTY, fullPath);
-
-            // StorageFolder.Delete ignores readonly attribute.  Detect and throw.
-            if ((folder.Attributes & WinRTFileAttributes.ReadOnly) == WinRTFileAttributes.ReadOnly)
-                throw new IOException(SR.Format(SR.UnauthorizedAccess_IODenied_Path, fullPath));
-
-            StorageFolder parentFolder = await folder.GetParentAsync().TranslateWinRTTask(fullPath, isDirectory: true);
-
-            // StorageFolder.Delete throws on hidden directories but we cannot prevent it.
-            await folder.DeleteAsync(StorageDeleteOption.PermanentDelete).TranslateWinRTTask(fullPath, isDirectory: true);
-
-            // WinRT will ignore failures to delete in cases where files are in use.
-            // Throw if the folder still remains after successful DeleteAsync
-            if (null != await (parentFolder.TryGetItemAsync(folder.Name)))
-                throw Win32Marshal.GetExceptionForWin32Error(Interop.Errors.ERROR_DIR_NOT_EMPTY, fullPath);
-        }
-
-        public override void SetAttributes(string fullPath, FileAttributes attributes)
-        {
-            EnsureBackgroundThread();
-            SynchronousResultOf(SetAttributesAsync(fullPath, attributes));
-        }
-
-        private async Task SetAttributesAsync(string fullPath, FileAttributes attributes)
-        {
-            IStorageItem item = await GetStorageItemAsync(fullPath).ConfigureAwait(false);
-
-            await SetAttributesAsync(item, attributes).ConfigureAwait(false);
-        }
-
-        private static async Task SetAttributesAsync(IStorageItem item, FileAttributes attributes)
-        {
-            BasicProperties basicProperties = await item.GetBasicPropertiesAsync().TranslateWinRTTask(item.Path);
-
-            // This works for only a subset of attributes, unsupported attributes are ignored.
-            // We don't mask the attributes since WinRT just ignores the unsupported ones and flowing
-            // them enables possible lightup in the future.
-            var property = new KeyValuePair<string, object>("System.FileAttributes", (UInt32)ConvertFileAttributes(attributes));
-            try
-            {
-                await basicProperties.SavePropertiesAsync(new[] { property }).AsTask().ConfigureAwait(false);
-            }
-            catch (Exception exception)
-            {
-                if (exception.HResult != HResults.ERROR_INVALID_PARAMETER)
-                    throw new ArgumentException(SR.Arg_InvalidFileAttrs);
-
-                throw exception.TranslateWinRTException(item.Path);
-            }
-        }
-
-        public override void SetCreationTime(string fullPath, DateTimeOffset time, bool asDirectory)
-        {
-            // intentionally noop : not supported
-            // "System.DateCreated" property is readonly
-        }
-
         public override void SetCurrentDirectory(string fullPath)
         {
             throw new PlatformNotSupportedException(); // https://github.com/dotnet/corefx/issues/17470
         }
 
-        public override void SetLastAccessTime(string fullPath, DateTimeOffset time, bool asDirectory)
-        {
-            // intentionally noop 
-            // "System.DateAccessed" property is readonly
-        }
-
-        public override void SetLastWriteTime(string fullPath, DateTimeOffset time, bool asDirectory)
-        {
-            // intentionally noop : not supported
-            // "System.DateModified" property is readonly
-        }
-
         public override string[] GetLogicalDrives()
         {
             return DriveInfoInternal.GetLogicalDrives();
diff --git a/src/System.IO.FileSystem/src/System/IO/WinRTFileSystemObject.cs b/src/System.IO.FileSystem/src/System/IO/WinRTFileSystemObject.cs
deleted file mode 100644
index a479fac8a9..0000000000
--- a/src/System.IO.FileSystem/src/System/IO/WinRTFileSystemObject.cs
+++ /dev/null
@@ -1,228 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System.Runtime.ExceptionServices;
-using System.Threading.Tasks;
-using Windows.Storage;
-using Windows.Storage.FileProperties;
-
-namespace System.IO
-{
-    partial class WinRTFileSystem
-    {
-        internal sealed class WinRTFileSystemObject : IFileSystemObject
-        {
-            private readonly bool _asDirectory;
-
-            // Cache the file/directory information
-            private readonly string _fullPath;
-
-            // Cache the file information
-            private IStorageItem _item;
-
-            // Cache any error retrieving the file/directory information
-            // We use this field in conjunction with the Refresh method which should never throw.
-            // If we succeed this is null, on failure we capture the Exception so that we can
-            // throw it when attempting to access the cached info later.
-            private ExceptionDispatchInfo _initializationException;
-
-            public WinRTFileSystemObject(string fullPath, bool asDirectory)
-            {
-                _asDirectory = asDirectory;
-                _fullPath = fullPath;
-                _item = null;
-                _initializationException = null;
-            }
-
-            public FileAttributes Attributes
-            {
-                get
-                {
-                    EnsureItemInitialized();
-
-                    if (_item == null)
-                        return (FileAttributes)(-1);
-
-                    return ConvertFileAttributes(_item.Attributes);
-                }
-                set
-                {
-                    EnsureItemExists();
-                    EnsureBackgroundThread();
-
-                    try
-                    {
-                        SynchronousResultOf(SetAttributesAsync(_item, value));
-                    }
-                    catch (UnauthorizedAccessException)
-                    {
-                        // For consistency with Win32 we remap ACCESS_DENIED to ArgumentException
-                        // Intentionally omit argument name since this is mimicking the Win32 sourced ArgumentException
-                        throw new ArgumentException(SR.UnauthorizedAccess_IODenied_NoPathName /*, intentionally omitted*/);
-                    }
-                    // reset our attributes
-                    _item = null;
-                }
-            }
-
-            public DateTimeOffset CreationTime
-            {
-                get
-                {
-                    EnsureItemInitialized();
-
-                    if (_item == null)
-                        return DateTimeOffset.FromFileTime(0);
-
-                    return _item.DateCreated;
-                }
-                set
-                {
-                    EnsureItemExists();
-                    // intentionally noop : not supported
-                }
-            }
-
-            public bool Exists
-            {
-                get
-                {
-                    // Do not throw
-                    if (_item == null)
-                        Refresh();
-
-                    if (_item == null)
-                        return false;
-
-                    return _item.IsOfType(_asDirectory ? StorageItemTypes.Folder : StorageItemTypes.File);
-                }
-            }
-
-            public DateTimeOffset LastAccessTime
-            {
-                get
-                {
-                    EnsureItemInitialized();
-
-                    if (_item == null)
-                        return DateTimeOffset.FromFileTime(0);
-
-                    EnsureBackgroundThread();
-                    return SynchronousResultOf(GetLastAccessTimeAsync(_item));
-                }
-                set
-                {
-                    EnsureItemExists();
-                    // intentionally noop : not supported
-                }
-            }
-
-            public DateTimeOffset LastWriteTime
-            {
-                get
-                {
-                    EnsureItemInitialized();
-
-                    if (_item == null)
-                        return DateTimeOffset.FromFileTime(0);
-
-                    EnsureBackgroundThread();
-                    return SynchronousResultOf(GetLastWriteTimeAsync(_item));
-                }
-                set
-                {
-                    EnsureItemExists();
-                    // intentionally noop : not supported
-                }
-            }
-
-            public long Length
-            {
-                get
-                {
-                    EnsureItemExists();
-                    EnsureBackgroundThread();
-                    return (long)SynchronousResultOf(GetLengthAsync());
-                }
-            }
-
-            private async Task<ulong> GetLengthAsync()
-            {
-                BasicProperties properties = await _item.GetBasicPropertiesAsync().TranslateWinRTTask(_fullPath, _asDirectory);
-                return properties.Size;
-            }
-
-            // Consumes cached file/directory information and throw if any error occurred retrieving 
-            // it, including file not found.
-            private void EnsureItemExists()
-            {
-                // If we've already tried and failed to get the item, throw
-                if (_initializationException != null)
-                    _initializationException.Throw();
-
-                // We don't have the item, try and get it allowing any exception to be thrown
-                if (_item == null)
-                {
-                    EnsureBackgroundThread();
-                    _item = SynchronousResultOf(GetStorageItemAsync(_fullPath));
-                }
-            }
-
-            private void EnsureItemInitialized()
-            {
-                // Refresh only if we haven't already done so once.
-                if (_item == null && _initializationException == null)
-                {
-                    // Refresh will ignore file-not-found errors.
-                    Refresh();
-                }
-
-                // Refresh was unable to initialize the data
-                if (_initializationException != null)
-                    _initializationException.Throw();
-            }
-
-            public void Refresh()
-            {
-                EnsureBackgroundThread();
-                SynchronousResultOf(RefreshAsync());
-            }
-
-            // Similar to WinRTFileSystem.TryGetStorageItemAsync but we only 
-            // want to capture exceptions that are not related to file not 
-            // found.  This matches the behavior of the Win32 implementation.
-            private async Task RefreshAsync()
-            {
-                string directoryPath, itemName;
-                _item = null;
-                _initializationException = null;
-
-                try
-                {
-                    PathHelpers.SplitDirectoryFile(_fullPath, out directoryPath, out itemName);
-
-                    StorageFolder parent = null;
-
-                    try
-                    {
-                        parent = await StorageFolder.GetFolderFromPathAsync(directoryPath).TranslateWinRTTask(directoryPath, isDirectory: true);
-                    }
-                    catch (DirectoryNotFoundException)
-                    {
-                        // Ignore DirectoryNotFound, in this case we just return null;
-                    }
-
-                    if (String.IsNullOrEmpty(itemName) || null == parent)
-                        _item = parent;
-                    else
-                        _item = await parent.TryGetItemAsync(itemName).TranslateWinRTTask(_fullPath);
-                }
-                catch (Exception e)
-                {
-                    _initializationException = ExceptionDispatchInfo.Capture(e);
-                }
-            }
-        }
-    }
-}
diff --git a/src/System.IO.FileSystem/tests/Directory/CreateDirectory.cs b/src/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
index a5db695dc5..641f11cd71 100644
--- a/src/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
+++ b/src/System.IO.FileSystem/tests/Directory/CreateDirectory.cs
@@ -36,7 +36,7 @@ namespace System.IO.Tests
         public void PathWithInvalidCharactersAsPath_ThrowsArgumentException(string invalidPath)
         {
             if (invalidPath.Equals(@"\\?\") && !PathFeatures.IsUsingLegacyPathNormalization())
-                Assert.Throws<IOException>(() => Create(invalidPath));
+                AssertExtensions.ThrowsAny<IOException, UnauthorizedAccessException>(() => Create(invalidPath));
             else if (invalidPath.Contains(@"\\?\") && !PathFeatures.IsUsingLegacyPathNormalization())
                 Assert.Throws<DirectoryNotFoundException>(() => Create(invalidPath));
             else
diff --git a/src/System.IO.FileSystem/tests/FileStream/ctor_str_fm_fa_fs.delete.cs b/src/System.IO.FileSystem/tests/FileStream/ctor_str_fm_fa_fs.delete.cs
index 2d45705429..dcd4978f57 100644
--- a/src/System.IO.FileSystem/tests/FileStream/ctor_str_fm_fa_fs.delete.cs
+++ b/src/System.IO.FileSystem/tests/FileStream/ctor_str_fm_fa_fs.delete.cs
@@ -84,6 +84,7 @@ namespace System.IO.Tests
                 Assert.True(File.Exists(newFileName));
             }
         }
+
         [Fact]
         [PlatformSpecific(TestPlatforms.Windows)] // file sharing restriction limitations on Unix
         public void FileShareDeleteExistingMultipleClients()
@@ -95,7 +96,7 @@ namespace System.IO.Tests
                 fs.WriteByte(0);
             }
 
-            Assert.True(File.Exists(fileName));
+            Assert.True(File.Exists(fileName), $"'{fileName}' should exist after creating and closing filestream.");
 
             using (FileStream fs1 = CreateFileStream(fileName, FileMode.Open, FileAccess.ReadWrite, FileShare.Delete | FileShare.ReadWrite))
             {
@@ -103,7 +104,7 @@ namespace System.IO.Tests
                 {
                     File.Delete(fileName);
                     Assert.Equal(0, fs2.ReadByte());
-                    Assert.True(File.Exists(fileName));
+                    Assert.True(File.Exists(fileName), $"'{fileName}' should still exist after calling delete with two handles open.");
                 }
 
                 Assert.Equal(0, fs1.ReadByte());
@@ -112,7 +113,7 @@ namespace System.IO.Tests
                 // Any attempt to reopen a file in pending-delete state will return Access-denied
                 Assert.Throws<UnauthorizedAccessException>(() => CreateFileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Delete | FileShare.ReadWrite));
 
-                Assert.True(File.Exists(fileName));
+                Assert.True(File.Exists(fileName), $"'{fileName}' should still exist after calling delete with inner filestream closed.");
             }
 
             Assert.False(File.Exists(fileName));
diff --git a/src/System.IO.FileSystem/tests/Performance/System.IO.FileSystem.Performance.Tests.csproj b/src/System.IO.FileSystem/tests/Performance/System.IO.FileSystem.Performance.Tests.csproj
index 85258bbfe6..14a24cd377 100644
--- a/src/System.IO.FileSystem/tests/Performance/System.IO.FileSystem.Performance.Tests.csproj
+++ b/src/System.IO.FileSystem/tests/Performance/System.IO.FileSystem.Performance.Tests.csproj
@@ -23,15 +23,9 @@
     <Compile Include="$(CommonTestPath)\System\PerfUtils.cs">
       <Link>Common\System\PerfUtils.cs</Link>
     </Compile>
-    <Compile Include="$(CommonTestPath)\System\IO\FileCleanupTestBase.cs">
-      <Link>Common\System\IO\FileCleanupTestBase.cs</Link>
-    </Compile>
     <Compile Include="$(CommonTestPath)\System\IO\PathFeatures.cs">
       <Link>Common\System\IO\PathFeatures.cs</Link>
     </Compile>
-    <Compile Include="$(CommonTestPath)\System\Diagnostics\RemoteExecutorTestBase.cs">
-      <Link>Common\System\Diagnostics\RemoteExecutorTestBase.cs</Link>
-    </Compile>
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="$(CommonPath)\..\perf\PerfRunner\PerfRunner.csproj">
diff --git a/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj b/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
index 0332976b83..b57b70ef61 100644
--- a/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
+++ b/src/System.IO.FileSystem/tests/System.IO.FileSystem.Tests.csproj
@@ -159,9 +159,6 @@
     <Compile Include="FileInfo\AppendText.cs" />
     <Compile Include="FileInfo\CopyTo.cs" />
     <!-- Helpers -->
-    <Compile Include="$(CommonTestPath)\System\IO\FileCleanupTestBase.cs">
-      <Link>Common\System\IO\FileCleanupTestBase.cs</Link>
-    </Compile>
     <Compile Include="$(CommonTestPath)\System\IO\TempFile.cs">
       <Link>Common\System\IO\TempFile.cs</Link>
     </Compile>
@@ -171,9 +168,6 @@
     <Compile Include="$(CommonTestPath)\System\PlatformDetection.cs">
       <Link>Common\System\PlatformDetection.cs</Link>
     </Compile>
-    <Compile Include="$(CommonTestPath)\System\Diagnostics\RemoteExecutorTestBase.cs">
-      <Link>Common\System\Diagnostics\RemoteExecutorTestBase.cs</Link>
-    </Compile>
     <Compile Include="$(CommonTestPath)\System\AssertExtensions.cs">
       <Link>Common\System\AssertExtensions.cs</Link>
     </Compile>