Numerous clients reporting this today, just a heads up, looks like a recent def push might have caused this. All the clients in question have XP, version 6, and all are reporting the issue - Avast crashes, can cannot be updated via the app. Loading a newer version fixes the issue. Just an FYI to anyone else having an issue.
Yea, me too. Had to boot in safe mode and uninstall AIS to get into the system again. 
Did the latest vps update fix this issue? ???
130410-1
Yep, I got this problem too. Can’t do a repair, can’t do a scan. Also, there’s no volume control in my task bar. Hmm? I can play an mp3 and it comes out the speaker so I know the sound card is working, but when I click somewhere where I usually get a beep through the speaker, I get a beep in the computer speaker.
I have avast version 6.0.1367. definitions say “unkown”. Can’t update or even run a scan. Says ‘service is not running’ for everything I try.
Thanks.
Download and run the VPS from here http://www.avast.com/download-update
Hi Essexboy! Thanks. I just read about this in another thread shared by ‘M_W’ and then repeated by ‘igor’. I downloaded ‘vpsupd.exe’, ran it, then rebooted and Voila!! All is fixed… and even my speaker volume control is back in my taskbar. Strange that it was affected as well. I had bunches of those ‘unpxxxxxxx’ files that igor wanted us to look for. Probably because I tried to do a repair through control panel.
Even though I’m on an older vers of avast, I still like it. Every so often it has a hiccup, but all in all it’s pretty reliable.
Thanks.