Error Your mailbox has reached its size limit and the mailbox cleanup wizard appears.

I receive an error "Your Mailbox Has Reached Its Size Limit" and the mailbox cleanup wizard appears.

This problem occurs when a person upgrades from Office XP and their off line folder OST has reached the 2GB limit. Outlook 2003 can use a unicode OST which has no limit but has no option to convert the older OST file to Unicode.

SOLUTION: Rename the old OST and then create a new Outlook profile using cached exchange mode. This will create a new Unicode OST file that has no limit.