We've identified a rather peculiar issue with the Zimbra preferences pane in both Snow Leopard and Lion.

Every few days, contacts and calendar stop syncing, and the user is presented with quite literally dozens of System Preferences instances, all of which display the message "System Preferences must restart in 32-bit mode" or similar. Clicking either in the affirmative or negative dismisses the window. This "32-bit mode" warning is typical when one wishes to go into the Zimbra preference pane manually.

Upon going into the Zimbra preference pane, the "traffic light" shows red, and the message in the bottom right corner shows an authentication error, despite all settings being correct. Simply re-entering either the username or password immediately resolves the problem.

It's almost as if, every few days the Zimbra connector just "forgets" either the username or password, and from that point on authentication fails. I suspect that the multiple instances of System Preferences is the connector's attempt at bringing itself to the foreground to report this authentication failure, but since it can't click OK on the 32-bit warning, it simply opens further instances of itself ad nauseam.

If it has a bearing, in every case the Zimbra server is remote, that is to say accessible via the internet connection rather than on the local LAN.

Is anyone else seeing this issue at all? We've seen it so far on 2 Snow Leopard and 2 Lion machines, all running in different locations.

Thanks in advance.