when starting-up antivirus error message appear unknown error. 42000 unknown error.
udell, welcome to the forums!
from my own experience, it would be best if you could tell us more about your system...
your operating system, any firewall you have, version of Avast! (Home or Pro)--any specs that you can add.
also, when does the error message start exactly?
I am not an experienced user, but others will need this information in order to help you. They have been much help to me...
Annie