Zone alarm and Avast are not compatible
Myth
ZoneAlarm and Avast are not compatible.They must not be installed on the same PC
Reality
You can run both Avast and ZoneAlarm on the same PC.
Explanation:
If you installed Avast on a PC already equipped with ZoneAlarm, you will have a pop up window informing you that there is compatibility problem concerning Web Filtering.
ZoneAlarm primary function is to act as a firewall, but also perform web filtering and act as an antivirus. As for Avast, it is an antivirus capable of performing web filtering. In order to prevent any conflicts be sure that ZoneAlarm and Avast are not performing the same tasks.
Conclusion:
You can have Avast running a antivirus, but don’t forget to disable all functions (antivirus protection, web filter) on ZoneAlarm, keeping only the firewall option enabled.