Or downloaded then installed? It would be strange to find a "download only" causing problems.
What problems were you having? You mentioned Windows Updates, but what else?
Any error messages when Windows Updates did not work?
If this Avast includes a firewall then I suspect the firewall component may have been blocking WU.
I downloaded the newest version and started having problems. The only other thing I downloaded after avast was spotify. After that, could not do windows updates. Uninstalled spotify, still could not update. Uninstalled Avast, and was able to do windows updates. I have no other antivirus software on the computer.