@Alycat:
Ok, I will enable logging.
But I know which files, I sat and watched, when I get that Windows box (second above, except it says powerarchiver.exe) everything is greyed, and in the list of files backed up errors start to appear. When I click that box to allow it, all starts up again ok, except for those file errors when it was grey.
ok, so you can use vss settings for these files to make sure they are backed up.