I'm having the exact same problem. In addition to that, I just uninstalled and re-installed the Avast Browser, and now I'm no longer able to clear away the massive amount of cache it leaves behind using CCleaner, like I was able to before. When I open up the private browser, the Adblock lever is switched off. I switch it on, but it doesn't do anything. It doesn't work on whatever website I visit next. If there's no solution to either of these issues, I'm just going to uninstall it for good. I don't like perpetually having 37 files in my cache that I can't get rid of without "Administrator Permission" (whatever that is). Incidentally, my computer is a Lenovo all-in-one.