Updated the Win7 x64 rig via the inbuilt updater a few hours ago. It required 2 reboots before the GUI would load properly (first time I got the "this is embarrassing" message) but it's loading fine now. The behaviour shield also required turning on manually after the first reboot, but it turned on automatically on the second.
A couple of things I have noted since updating:
1. When you run a scan and check the scan history it now says the run time is "a few seconds", when in actual fact the scan I just ran took an hour. So I checked the history of old scans run well before the update today and it appears to have changed them all to only " a few seconds" in the run time field too. A full scan on this tired old rig takes a good few hours. The amount of data tested appears accurate, it's just the run time that's off.
2. Someone in a comment on the main part of this form mentioned their avast tray icon wasn't animating on this updated version. Mine is animating when it is scanning - I'm pretty sure it was broken on the previous version(s) but is working again now.
3. I created a custom scan in the last version after avast! removed the quick scan. I used pretty much the same settings as the old quick scan (taken off a computer I hadn't updated at the time), only I adjusted the sensitivity from low to normal, and I added modules loaded in memory to "scan areas". After this update today I notice avast! has altered my custom scan. Before the update my custom scan was named "My Quick Scan" with no description in the comment field. The name has been changed to "Quick Scan" and a description has been added in the comment field of the settings saying "Performs a scan of the areas on your computer most susceptible to malware infection". I did not add a comment when I created the scan! It also reconfigured the scan back to low sensitivity, and removed the modules loaded from memory option in the "scan areas". I have since adjusted it back to how I had it before the update. It's good if avast! have bought the quick scan back (?), but I think it should have been added as a standalone scan like the full scan, targeted scan, & boot time scans are; rather than altering someone's custom scan.
EDIT - Have now updated Win10 x64 machine via the internal updater - went completely smoothly. No need for second reboot.
1. Same issue on this computer with the run time for scans in the scan history showing "a few seconds", including scans before the update which took about 30mins from memory.
2. Avast tray icon has been fixed and appears to be animating again on this machine too.

3. The update has removed the custom scan I created called "My Quick Scan" on this machine too, and replaced it with a "Quick Scan" using avasts default quick scan settings. I have kept this and created my own version of a Quick Scan with slightly tweaked settings. I'm annoyed that avast removed a custom scan but glad to see they've re-thought removing the quick scan. It's a good alternative to the full scan (which I run only once a month or so) and the smart scan, whgich I personally never run because I don't think it's adequate for anything.