opensubdiv/osd/d3d11VertexBuffer.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/opensubdiv/osd/d3d11VertexBuffer.cpp b/opensubdiv/osd/d3d11VertexBuffer.cpp
index 603cbf4..07e7e0a 100644
--- a/opensubdiv/osd/d3d11VertexBuffer.cpp
+++ b/opensubdiv/osd/d3d11VertexBuffer.cpp
@@ -81,7 +81,7 @@ D3D11VertexBuffer::UpdateData(const float *src, int startVertex, int numVertices
 
     deviceContext->Unmap(_uploadBuffer, 0);
 
-    D3D11_BOX srcBox = { 0, 0, 0, size, 1, 1 };
+    D3D11_BOX srcBox = { 0, 0, 0, (UINT) size, 1, 1 };
     deviceContext->CopySubresourceRegion(_buffer, 0, 0, 0, 0,
                                          _uploadBuffer, 0, &srcBox);
 }