"AV engine is not initialized" error after update to ver 12.x

CIS on WinXP-32:
AV definitions updates stoped working after automatic update to ver 12.x:
“Update failed. AV engine is not initialized”

Without more info, it is hard to give advice. I would use System Restore to revert to prior the update, then do a fresh install of the latest version

Hope it helps

Cheers

Try running Diagnostics and see what it says and if it manages to fix it. It can be found under Miscelaneous.