I just found that out by trying to install Avast. Your post with the cleaner tool saved my skin! Quite a let down from Avast when they have known about the Anniversary Update for quite a bit of time....

I am running Avast. I tried with it enabled and disabled. I finally just gave up and created a bootable USD disk after reading how to. Installed the Anniversary Update this way.

Having this same exact issue. System Thread Not Handled at 71%. Thought it was my anti-virus...disabled that. Same thing. Not sure what is going on here. Not computer literate at all so I guess I...