system
9
I lost my virus definition update notices and voice as well after updating to the newest Avast! I had both check marks under community features unchecked. I decided to try checking them both and restarting my computer. Now I have my voice and update pop ups working again.
Try opening Avast! and going to settings. Choose appearance on the left and scroll all the way down to Community features and make sure both boxes are checked. Restart computer and hopefully your definition updates and voice will return.