I decided i would post this on documentation since i have not seen much about VSS issues. However, i was having an issue with VSS Exception errors occurring on 3 of the windows XP machines that we backup. It was a fairly new error as they backed up fine previously. After trying the 100th different documentations online about VSS errors i said screw it lets reinstall urbackup… Upon installation i saw that i uninstalled version 2.1.15… i was like odd… this version can’t install on windows XP… As it turns out. After having installed version 1.4.9 my server had automatic silent upgrades enabled. Come to find out, the silent install bypasses the Windowx XP expiration notice and allows the install anyways and allows the backups to proceed but cases VSS errors.
So all in all after a week and a half of troubleshooting … autoupdate was at fault here. I backed up my ident keys uninstalled 2.1.15 and reinstalled 1.4.9 and put my XP machines in a group that does not allow the silent upgrades.
I hope this helps!!