it only happens on the nvidia chipset box - after auto-update Avast is quasi freezing the box, no icon spin but the HDD is shuffling. Only way out is boot into safe-mode uninstall avast and all is normal after the next bootup. Then I install Avast again and it usually works - this happened now twice to my wife's box!
Another Avast annoyance on the nvidia box is it
always wants to install the complete software (green notification). Never saw on this box a blue notification.
No problems like this on the Ali chipset system.
I hope you get the problem fixed quick or my wife tells me to dump Avast