How to get rid of a phantom voice mailbox? Somehow I wound up creating a Distribution List Mailbox without any distributee extensions instead of a Subscriber mailbox. The DLM doesn't show up in any of the menus, so I can't delete it. It does show up in the Archive and Restore processes. When I try to create a proper subscriber mailbox under the same extension number, it tells me that a DLM already exists for that extension number.

From the Mailbox Configuration menu, enter the DLM number, select Edit. This should bring up the mailbox. Then press F9 to delete the mailbox. It sounds to me like you may have already tried to delete it and its still 'out there'. You may have some corruption in the database. Have you tried running a Database Fixup or Database Reconciliation?