Updated one Windows 7 machine - no problem. Updated a second machine, Avast blocked web access from IE and intermittently caused black screen after logging onto the user account, forcing a power off restart. Had to remove in safe mode and reinstall back to 1466, no problem now.
Between the buggy update earlier this year (1453?) and 1473, I've spent more hours this year uninstalling and reinstalling Avast than in all the many years I've been using the product. All three of my Windows 7 machines have been disabled by one or the other of these two releases, and one machine has been disabled by both. This product is like a high-maintenance girlfriend, about to get dumped.