Feb 23
Problem: You got a huge mailbox but the AutoArchive feature does not work.
Symptom: Old elements in outlook stay where they were even though the date is older than the time you specified in the AutoArchive settings.
Reason: If you edit, move, copy, forward or reply to an element, the message modification date is set to the time of the action taken. AutoArchive does check for that date, this is the reason why some elements may remain in the inbox or in the calendar even if they seem to be older and should be in the archive.
MS KB: KB197981 even if this article is said to apply to outlook 2000 it’s still applicable for 2003 and 2007