Ok ... After using Avast for a very long time, I too have come unstuck with this latest update.
Perfectly stable laptop, running Win7 Pro x64
Had just performed a cold reboot prior to updating my accounting software. This restart was normal. Prior to doing anything else, Avast announced the update.
Like others, a no brainer I thought. Didn't get to update the accounting package.
My laptop has an SSD and usually boots in under 30 seconds, it is completely stable and well maintained. Until this update. I am still staring at a spinning wheel and 'Welcome' after 6 minutes. No desktop
How certain am I this is Avast related? Given a normal reboot immediately prior, about as certain as you can be.
I will attempt uninstall / removal in Safe mode (I can get a desktop) unless something happens in the next 5 minutes.
At this stage, this is more of a boot failure than slow boot. Not happy.
4 other computers in the house won't be getting an update till this is sorted.