It stopped working saying can't load xpcom. When trying to download new thunderbird Avast finds a virus although the claim is The file named XUL. DLL is developed by Mozilla Foundation. The program is primarily used by the software XUL Runner. The file is confirmed to be safe because it is supported by the original developer Mozilla and is used by the popular browser Firefox. The file has not been involved in any virus issue earlier. win64-evo-gen:[Trj]