Avast makes Win 8.1 Modern Apps unusable

I have had no a few times in Win 8.1 that when updating an App from the Windows App Store, that Avast has put the programme in a state that it will not startup again.
It recognizes it as a virus, and makes the App unowrkable >:(

I have now uninstalled Avast, everything is working fine again.
However I would like to know what to do on it, so that my system is also protected again.

Joost

You can report a possible FP here: https://www.avast.com/contact-us.php?subject=VIRUS-FILE

Can you list an App that’s giving you the problem ???
Are you getting any error messages ???
Can you post a screenshot ???
I just finished doing some updates on Apps without problems.