I too have reported this in another forum thread.
I'm running Win 7 Ultimate, and this UI/service crashing began yesterday, 1st February 2018, on my Desktop and another unconnected W7 laptop, both of which are running paid for Avast Internet Protection.
There have been no Windows updates on this machine since 10th January, so that seems an unlikely cause.
So far, I have:-
- made sure the Remote Desktop service is set to Auto and running
- done at least 2 repairs of the installed program from Win Control Panel>Programs
- done a complete fresh install of Avast Internet Protection using avastclear, deleting driver files and program folders etc. as detailed by Avast
- run the avastsupport tool and sent them the results this morning
- torn out a lot of hair
The crash rate seems to have stepped up to about every 10 minutes or so on both machines.
I notice that, having followed the UI restart Avast screen lately, I now have two (both unkillable) instances of AvastUI running, at different sizes, in the Task Manager viewer.
This is really irritating, and not good for a product for which I've paid. Most galling is the lack of explanation of the causes of this, and endless re-installs and repairs aren't the answer; certainly not here.