Avast stops

I’m home from work today and decided to do a thorough scan of my hardrive, but Avast keeps stalling. After it had run over an hour, it was stuck on TweakUi.exe installation file in my documents. I deleted it and restarted. Came back hour later and its stuck on a tiny .bmp file in same folder. Avast wont close. I have to use Task Manager to shut it off. “Program not responding”
If I try regular scan it goes. Will not complete a thorough scan.

That’s strange… if you copy the file (where it stalled) somewhere else and scan only this single file (thorough, with archives) - does the same happen?

I deleted the TweakUI and renamed the .bmp file. I right click both and had avast scan and it worked. Confusing. Third try at thorough scan and it completed. Glitch somewhere.