Also having this problem for past 1-2 days where right click scan shows no popup saying it's scanning or scan complete with green check marker.
It will do it only once and that's when I restart my computer. First scan will have popup then none for any other scans.
It's kind of annoying having to keep the main avast window open, then tab to whatever file/folder to scan, then tab back to main avast window to see it's scan progress.
Tried reinstalling Avast, but it didn't fix as well.