Hi,
for one of the user accounts (my own) on our home PC the avast GUI freezes after being opened, ie the avast window shows but is non-responsive. Drastic reinstallation of avast seemed to help as long as I remained in the free, limited version, but as soon as I activated Avast internet security, the GUI started freezing again. For other users (wife, children, admin) on the same PC there is no problem.