Well it has been an extremely long time since I used 18.8 on my old XP system and it didn’t give a graceful exit, but as far as I can recall it did have the X top right (and the key stroke option I suggested did work. Just in case, there are two Alt keys on most keyboards, it is the one on the Left side of the keyboard.
However, it would appear something has changed, which it shouldn’t have in what is effectively a closed version.
Again previously you could ignore the nags and after 13 days (I can’t recall the exact time frame), but eventually it would renew itself.
Today when I got the license expired screen in Avast and clicked re-activate, I got a different screen.
It offers Premium, but has ‘no thanks’. Clicking ‘no thanks’ puts you back to the original screen. No activation.
I noticed Avastsvc.exe was no longer running. So protection was dead
I re-installed. But for the 1st few boots got the license expired screen, then the you are protected screen.
Avast is anxious to get rid of free users it seems.
I would suggest it is more the issue of still having an unsupported OS resulting in having an old and no longer supported Avast Version.
I have only been using Avast Free for 20 years. It fits my needs and I also have some other areas covered. I also make regular system and data backups.
Registration of Avast 18 has not been working since 2022.
Reinstall of Avast removes current licenses, and as you can’t get a new one as registration not working, Avast 18 enters some kind of fallback-mode that works without license, that is the screen you are seeing (expired => protected change).