I just had a problem with my Version 5 upgrade from 4.10. Technically the upgrade technically went very good, except for one problem.
The CEO of our company, his email account had the following problem....
Most of his email would go to his email box without any problems, but certain emails were getting stuck in the deferred que with the message "Content Filter: Undefined...."
After trying just about everything, this is what worked (or appears to be working.)
1. set up a new user account (I don't use the email address as the user account name)
2. moved all the aliases and the connical name to the new user account, so it would catch all new email.
3. Renamed his original email account to firstname.lastname@example.org (replace example.com with your domain)
4. created an Active Directory logon account to match
5. Renamed the new account to match his old one.
6. Using outlook, logged into windows using username_b and exported all his existing email to a PST file.
7. logged back into windows using his normal user name (not username_b but username)
8. Removed his old Outlook settings
9. Set up from scratch his Outlook connector for Zimbra
10. Imported the pst file created in step 6.
11. Restart Zimbra
12. On new email account be sure any groups, increased email quotas, enable functionality that was there before.
12. After a few days delete the old zimbra and active directory accounts.