One other suggestion, with the firewall, is to clean out any application rules for avast services from 4.8 which no longer exist, there were several of them. Comodo, back when I used that, had a "purge" button which would automatically run through the list of permissions and delete any lines for which the corresponding application or service was no longer onboard.
The PC Tools one that I now use requires you to remove them manually and individually -- but if you untick that "hide uninstalled" thing, it'll flag each of those with a red X.