had a user that was having issues with the zimbra connector (5.0.12), giving errors when trying to move items from folder to folder and after a restart just opening Outlook would error with cannot read default mail file (zimbra zdb) and close. Tried recreating profile, etc.
noticed when uninstall/reinstalling the zimbra connector that a bunch of MS LIVE stuff was installed and we don't install that here. The user had updated MS Messenger which contained some LIVE items (not sure what else came over) ... but after removed everything that said LIVE in it and restarting, everything is fine.
Seen a MS Exchange LIVE connector that was disabled in the COM items, but didn't actually fix until fully removed.
HTH someone else..........