I have a user with 52,7GB in the mailbox and to say the least its flaky at best. Works fine in webmail but Outlook has issues.
Mails come in and blinks in the inbox folder but are gone right away.

Changing his settings in the offline folder makes it work for a while.

Total size is 52,7GB reported in webmail and 57GB in outlook.
How to bring that down?? Archiving doesnt bring the total filesize down and setting a clean setting in webmail does nothing.