Exchange::Mailbox Cleanup Agent

Thanks to: MS Exchange Team Blog

Exchange 2000/2003 Mailbox Manager and msExchMailboxManagerAgeLimit.
In Exchange 2000/2003 mailbox manager policies may not process items as some administrators might expect. For example, if you set up a mailbox manager policy to delete messages from the inbox after 30 days, you may find that some of the messages are not deleted after the 30 day window has passed.

In Exchange 2000/2003, in order for a message to be processed by a policy, the age of the message must pass 3 criteria:

Delivery: (PR_MESSAGE_DELIVERY_TIME),

Sent: (PR_CLIENT_SUBMIT_TIME),

and Last Modified: (PR_LAST_MODIFICATION_TIME).

If any of these flags are less than the age specified on the mailbox manager policy settings, that message will not be processed. In other words, if you have a policy set to 30 days and at 29 days a user reads a message that falls under this policy (and hence sets the last modified flag back to 0 days) the message will not be processed after the 30th day because it will fail on 1 of the 3 criteria. It will not be processed until all the criteria are met (in this scenario after 30 more days)

This behavior is different than in Exchange 5.5. In Exchange 5.5, if the delivery time flag is present on a message then no other criteria will be checked. So in the above scenario, 30 days after receiving the message it would be purged.

The design was changed in Exchange 2000/2003 to better accommodate certain workflow programs, journaling and non-ipm.note message classes that would look at different message properties for cleanup.

However, in certain environments you might want to have Exchange 2000/2003 behave the same as Exchange 5.5. This can be done in Exchange 2000 with the post SP3 roll-up or with Exchange 2003 RTM by setting the msExchMailboxManagerAgeLimit attribute on the mailbox manager policy to a hex value of "0x3".

There are three values you can set this to depending on your needs:

0x1: The Last modification time will not prevent the deletion of a message. If the last modified modified date is greater than the limit, the item may be deleted.

0x2: The time that the message was submitted will not prevent the deletion of a message. If the submission time is greater than the limit, the item may be deleted.

0x3: This value sets both bits 0x1 and 0x2, and mimics the behavior from Exchange 5.5.

Note that Mailbox Manager does not ever delete recurring appointments or tasks, regardless of age. You cannot turn off evaluation of delivery time.

More information on setting this is in the following article: KB 326397