diff --git a/llvm/lib/System/Win32/Path.inc b/llvm/lib/System/Win32/Path.inc
index 4a6dbd3ddf29..64e7025fc9bf 100644
--- a/llvm/lib/System/Win32/Path.inc
+++ b/llvm/lib/System/Win32/Path.inc
@@ -745,12 +745,19 @@ bool Path::getMagicNumber(std::string& Magic, unsigned len) const {
   return true;
 }
 
+// Implements renamePathOnDisk as a CopyFile + eraseFromDisk on Windows.
+// Using MoveFileEx was causing mysterious ACCESS_DENIED error when used
+// within a multithreaded lit/python context.
+// FIXME: put back MoveFileEx when the source of the problem is resolved.
 bool
 Path::renamePathOnDisk(const Path& newName, std::string* ErrMsg) {
-  if (!MoveFileEx(path.c_str(), newName.c_str(), MOVEFILE_REPLACE_EXISTING))
-    return MakeErrMsg(ErrMsg, "Can't move '" + path + "' to '" + newName.path
-        + "': ");
-  return false;
+  if (*this == newName)
+    return false;
+  
+  if (CopyFile(newName, *this, ErrMsg))
+    return true;
+  
+  return eraseFromDisk(true, ErrMsg);
 }
 
 bool