I received this question a couple of times before and it might help who face this following scenario: The Administrator has just deleted an user and he wants to update the list of the disconnected mailbox in the Exchange Management Console to play with the disconnected mailbox but the user is not there. Using Exchange Server 2003 we have just to right-click on Mailbox under Mailbox Database and click on Run Cleanup agent option and the disconnected mailbox will show up but how about Exchange Server 2007?
It’s a piece of cake :) but in order to do that we have to use the following cmdlet, as it follows
clean-mailboxdatabase <mailbox database name>
More information about clean-mailboxdatabase cmdlet: http://technet.microsoft.com/en-us/library/bb124076(EXCHG.80).aspx
After running this cmdlet against your mailbox database, you will be able to see the user that was recently deleted on the disconnected mailboxes list.