Comment 3 for bug 1528767

Okay, sounds like the updater. It'd be handy to have the error message - if you ever see it again please keep it. :)

It looks like it'll actually clean up the UpdateDirty and UpdateStage directories even on failure, so we might be able to do some better recovery here. If it failed moving the files from the main directory to UpdateDirty, is *should* be able to move everything back (though there's no guarantee with the way some anti-virus tools work, for example).