I'd like to report yet another similar problem.
Windows 7 Ultimate (32 bit)
No other security software installed
Updated to 5.1.889 from 5.0.667 (free versions).
AvastSvc.exe is crashing.
(snippit from Event Viewer)
"Faulting application name: AvastSvc.exe, version: 5.1.889.0, time stamp: 0x4d2ebaae"
"Faulting module name: ntdll.dll, version: 6.1.7600.16559, time stamp: 0x4ba9b21e"
"Exception code: 0xc0000005"
It "seemed" to be working fine at first after I updated, until I rebooted. Then windows threw up an application error in avastsvc.exe. Waited till windows is fully booted, and the avast notification icon had a red x. Launched the user interface, it says nothing was running and gives me an option to fix the condition. It goes and tries to restart the service, which is a 50/50 shot that it will work. If it does, it crashes again with the application error as soon as you do anything that triggers avast to want to scan (opening a file, trying to access the internet, etc..). Rebooted, same thing. Downgraded back to 5.0.667, no problems at all.
And before you ask, no, I did not follow your instructions above, and with good reason. Regardless if it works that way or not, it still fails to address the issue that avast is "supposed" to allow updates, which have always worked just fine in the past for me (been using avast for years). That updating to this particular version has seemingly caused various crashing problems for a lot of people, there is obviously a problem somewhere. That doing a clean install fixes it for some seems to indicate that maybe the updater app is botching things. But given that according to some replies on these forums, not even a clean install fixes the crashes with this particular version (but no problems with older versions), that comes back to v5.1.889 itself being bugged somewhere.
Further, this workaround requires you to enter safemode. Problem is when you use a screen res higher then windows default and have icons on your desktop. Safemode uses default screen res, and icons that are outside the resolution boundary are relocated willy-nilly to empty areas of the safemode desktop, then when you shutdown and reboot back to your normal resolution, all your desktop icons are messed up because windows saved the icon positions from when you were in safemode. Happens to me everytime since the Win95 days. Just another inconvenience that I as a user have to be forced to deal with because the avast program isn't functioning as advertised.
Sorry to be blunt, but that's not my problem to have to deal with. I mean, thank you for the advice on how to hopefully get it working, but instead of work being put on the users, someone needs to focus on fixing the issue causing the need for users to have to do that to begin with. That one has to do things they shouldn't have to do and normally don't need to do just to get this particular version to work says all that needs to be said right there when you think about it. When have those conditions ever "not" been related to fundamental problems in the program requiring that extra TLC. Never that I can think of in my nearly 30 years of PC use.
Thanks, but I'll stick with 5.0.667 for now. Something is obviously wrong somewhere with regards to this new version, and avast downplaying this isn't going to get it fixed any quicker (though it does make long time users question their loyalty towards avast.)