I just formatted my son’s pc, installed windows ME and avast. 75 gigs free space and when I try to update avast it gets to about 90% then stops and says there’s not enough space. I’ve attached screenshots, and the log.
Saw the same thing about a week ago on a W95 machine with 4.8.1229. Upgraded to 4.8.1296 and I think it then updated the definitions without error but I’ve not used it since.
Can you try to repair your installation?
Go to Control Panel > Add/Remove programs > avast! antivirus > Remove. Then choose Repair function in the popup window (Repair).