[redhat]

This must be something simple because the calendar works perfectly. Appointments made in Outlook show up right away in the Zimbra web interface.

Nothing in the log file that looks odd. In fact, I just looked at that again and there are no entries made in the log file during the synchronization process. Should something be logged?

I was watching the log while starting up Outlook. After Outlook loads I get a window pop up that says "2 of 2 tasks completed successfully" and below that it lists "Downloading GAL" and "Synchronizing" as the two tasks and both say "Completed." Then I get a second window pop up with the error message and "0 of 1 tasks have completed successfully" and the error below that says:

Task 'Zimbra Collaboration Server - Sending and Receiving' reported error (0x80040102) : 'The requested operation cannot be performed on this account'

UPDATE:

I just saw the note about using DebugView to capture some debug information. I ran DebugView and started up Outlook and waited for the error message. This is what appeared in the DebugView window:

[2424] First time patch on vtbl 0x360B4488
[2424] Addin::ctor
[2424] Addin::FinalConstruct

Not sure if that means anything or even if I'm using DebugView correctly. Hope it helps.