diff --git a/xpcom/io/nsLocalFileWin.cpp b/xpcom/io/nsLocalFileWin.cpp
--- a/xpcom/io/nsLocalFileWin.cpp
+++ b/xpcom/io/nsLocalFileWin.cpp
@@ -1448,17 +1448,39 @@ nsLocalFile::CopySingleFile(nsIFile *sou
         copyOK = ::CopyFileW(filePath.get(), destPath.get(), PR_TRUE);
     else {
 #ifndef WINCE
         copyOK = ::MoveFileExW(filePath.get(), destPath.get(),
                                MOVEFILE_REPLACE_EXISTING |
                                MOVEFILE_COPY_ALLOWED |
                                MOVEFILE_WRITE_THROUGH);
 #else
-        DeleteFile(destPath.get());
+        /* create local file for destPath */
+
+        nsCOMPtr<nsILocalFile> realDest = new nsLocalFile();
+        if (realDest == nsnull)
+            return NS_ERROR_OUT_OF_MEMORY;
+
+        rv = realDest->InitWithPath(destPath);
+
+        if (NS_FAILED(rv))
+            return rv;
+
+        /*
+        PRBool isdir;
+        if (realDest->IsDirectory(&isdir))
+            ::RemoveDirectoryW(destPath.get());
+        else
+            ::DeleteFileW(destPath.get());
+        */
+        rv = realDest->Remove(PR_TRUE);
+        
+        if (NS_FAILED(rv))
+            return rv;
+
         copyOK = :: MoveFileW(filePath.get(), destPath.get());
 #endif
     }
 
     if (!copyOK)  // CopyFile and MoveFileEx return zero at failure.
         rv = ConvertWinError(GetLastError());
 
 #ifndef WINCE