The scene: One distraught user, working on a Very Important Project (aren’t they all – this one really was, though), whose entire email heirarchy had duplicated itself and then systematically deleted all messages from within all folders (including contacts, calendars, etc).

The culprit: Entourage 2004, with all patches applied. And, an Exchange server migration of said users mailbox.

The solution: Who wants to wait around to restore from tape? The easiest way to fix this (without restoring from tape) is to have the user log into Outlook 2003 on a machine that has this registry fix applied: http://support.microsoft.com/kb/246153 – and then systematically restore deleted items from each subfolder.

If you do end up restoring from tape, delete the munged Exchange profile (not identity) within Entourage *before* the restore, and then recreate the Entourage profile after the restore is complete. Otherwise, this will be an endless cycle.