On many computers after installing Avast for the first time or updating the program the computer will not logoff or shutdown. When shut down or log off is picked from the start menu the computer just goes back to the desktop. Same thing if picked from Ctl-Alt-Del. The only way to get the computer to allow the user off is to unplug the power. After that the computer works normally until the next program update. Causes many desk visits from support.
Running Avast Business Protection Client and Windows XP or Windows 7 (Does it for both versions of OS).