Well the subject says it all really, for some time now the old defs folders remain, especially if you aren’t shutting your system down every night. On my XP system it has currently 734MB of defs sub-folders going back to 18030502.
Ordinarily I shutdown this desktop system but of late I have been leaving it on standby, but this was the same at times even when regularly shutdown there were many old defs sub-folders.
My win10 system laptop is normally left on standby and shutdown perhaps once a week if required by an update, etc. This also has sub-folders going back to 18030000 and 619MB in size.
Previously Avast housekeeping used to be quite good, there might have been two sub-folders current and previous, which I can see a reason for, backup/rollback in the event of a problem. now it is bloody terrible.
I do regular drive image backups on all systems to an external drive and I keep the last 5 drive images for all systems, so this amounts to a huge waste of space and time.
Also C:\Program Files\AVAST Software\Avast\setup where there a load of uniquely named folders (like hash/sha codes, whilst most of these are empty they are a pain.
In total the current size of the Avast Folder is 1.3GB and that doesn’t include all of the other locations with avast files in them. The avast housekeeping functions needs a bloody good kick in the pants.