When a mail-enabled user account is deleted from Active Directory or a mailbox is deleted using the Exchange Management Console, the mailbox should be held as a ‘Disconnected Mailbox’ according to the mailbox retention setting.
However, when you check the ‘Disconnected Mailbox’ node it is empty or does not contain a recently disconnected mailbox.
It may take anywhere between 15 minutes and an hour before a disconnected mailbox is listed.
If the mailbox is still not listed you will need to manually run the ‘Clean-MailboxDatabase’ commandlet on the mailbox database.
In this example the mailbox database is called ‘Mailbox Database 0995324840’.
Using the Exchange Management Shell, run the following command:
Clean-MailboxDatabase "Mailbox Database 0995324840"
When finished, the disconnected mailboxes can be found in the ‘Disconnected Mailbox’ node in the Exchange Management Console.