I run defraggler, and look at the file list:
4 Fragments 46,135KB C:\Program Files\AVAST Software\Avast\Setup
I have deleted the install file for avast, and this keeps getting fragmented over and over.
That's odd. We both have this. 
I haven't deleted any Alwil stuff.
Notice they're unchecked. I wouldn't touch it. Memorize it.
My happy guess – every day I have several fragged Alwil files, so it’s probably got something to do with the daily update.
My happy guess -- every day I have several fragged Alwil files, so it's probably got something to do with the daily update.
Avast tries to update every four hours by default, so it's of no surprise whatsoever that the signature files/detection files would gather fragments, I'd expect allot of antivirus/antimalware software to have the same "issue." The same happens with AntiVir Free however the biggest fragments it ever causes are with its avguard.tmp.