I think maybe Avast 5.1 was released too fast. I am going to wait for actually several weeks on this build. My 5.0 is running like a champion. Did any of you get a pop-up message about 5.1 being out? I didn't, and I don't really want it, until problems with this release are resolved. I still set my settings to "Ask When Update is Available." This helps me keep track. Usually, I will install the new version within a day to a week at most of notification, while watching the forum.
But I understand 5.1 has some new features, so maybe that is why there might be more bugs than in the past.
Jack