I noticed avast's behavior shield is the cause of most problems reported here
I experienced myself that the behavior shield mysteriously prevented a few of my programs to run without any notification. Repairing or clean installation didn't solve the problem
Yesterday, my friend told me that his low-end laptop was sluggish in all tasks and he asked me to looked for the cause because he's a basic user. I found that behavior shield was constantly using CPU ~0.1-1% and almost never stayed at 0%. A few of his programs couldn't run properly too
I decided to uninstall behavior shield and installed the minimum configuration (file & web shields) => his laptop was a lot more responsive and less buggy since then. I tweaked his setup with other programs instead of using avast's Behavior shield
I also noticed avast behavior shield turned of itself in the past
if there is any unsolvable problems, just try to disable Hardware virtualization, if doesn't work -> disable behavior shield -> problems solve