One of cool things you can do in Exchange 2003 using the Exchange_Mailbox WMI class in you can show all the disconnected mailboxes by querying the DateDiscoveredAbsentInDS property which gets set after the “Cleanup Agent” has detected that there is no longer a Active Directory account associated with this mailbox. To make this information really useful in a report you need to combine it with what the Mailbox retention settings are on the mail-store where this mailbox is located. This will tell you when the mailbox is going to be deleted and how many days it has left in the cache. This information may be interesting if you have a mailbox that is quite large and you want to know when that space will be recovered into the mail-store. It can also come in handy if you need to monitor your helpdesk staff to make sure they aren’t deleting any mailboxes they shouldn’t. eg you could use it to email a warning when there is only 2-3 days left before a mailbox will be permanently deleted to reall
Pushing the Envelope in Messaging and Office 365 Development