Avast is working perfectly for me in that build. In fact, it is working so well that it started blocking my entire internet connection to the outside world! It seems the change in how Windows 10 handles services on systems with a certain amount of RAM could be behind this monstrosity, although I'm not qualified enough to say for sure.
Same issue here. 9 out of 10 requests result in a 'This page cannot be displayed' message - disabling avast appears to be the only solution so far.
Replying to confirm.
Symptoms experienced: System 95% unresponsive, Solid 38-40% Avast Service CPU always. Eventual system lock - mouse moves but cannot open anything - no apps or right-clicks. No internet access at all.
Event sequence:
Windows Update completed update to 14942 overnight. Logging in fine. System extremely unresponsive - took minutes to load Task Manager which showed 'Avast Service' at a constant 38-40% solid. Managed to load Avast - nothing appeared running, no updates or auto-scans. All features of Avast uninstalled - strictily anti-virus file/web shield and Network security - other features uninstalled (so at least it wasn't an advanced feature doing this). Opened Avast, attempted 'Reinstall' which was needed long ago on Windows - seemed to cycle through reinstalling with progress bar - no change.
Rebooted... System now totally unresponsive. Unable to open anything, systray icons not loading. Avast still at 38%. Unable to load Programs and Features to uninstall. Ctrl-Alt-Del unresponsive - unable to reboot safely - hard reset. System was too unresponsive to consider reinstalling and based on past problems - (where Avast reinstall and a reboot had worked), researched this and decided to uninstall and wait.
Next boot quickly launched and uninstalled Avast successfully. shortly after - locked again. Hard reset - system back to normal functionality after uninstall. Trying another free AV while I await a solution - don't like it, look forward to the next build of Avast or Windows - whoever finds and fixes it first...