I was going to suggest to you an Avast Repair and if that didn't work an uninstall/clean install, but I see you already the the uninstall/clean install and it fixed your problem.
However you state that you have to do this with every upgrade, so something needs to be looked at.
What other security software do you currently have or did you have in the past on this machine including:
- Antivirus (AV)
- Firewall (FW)
- Trial versions of AV, FW and other security programs
- Other security software (on-demand and resident)
- If they were in the past, how did you remove them (the vendor's uninstaller's tool or another way)?
Is ZA FW still off your machine?
Is your machine up to date with MS/Windows updates? Thank you.