ZoneAlarm, long the favorite firewall out there, didn’t seem so great earlier this week. Apparently, the latest update to ZoneAlarm Pro and ZoneAlarm Security Suite caused a large number of crashes.

“There was somewhat of a process breakdown,” Freund said on Friday.

The Program Advisor update is a list of trusted programs that tells the firewall which applications should be allowed to connect to the Internet without user interaction. A new version of the list is produced daily. By default, ZoneAlarm products check on start-up for a new version and download and install it, Freund said.

Such errors can’t exactly be eliminated entirely, but can cause big problems, however temporarily. So many people and companies rely on ZoneLabs’ products to provide protection against mailicious attacks that a mistake can cause a lot of grief. At least it was corrected quickly.