It’s pretty common in an Exchange environment for users to have access to other users mailboxes. Permission can be given via the Exchange Management Console for users to access another mailbox from within Outlook (File > Open > Other User’s Folder), and, in theory, permission can be removed using the EMC as well. Unfortunately, even though permission is seemingly removed, it often leaves the now unnecessary mailbox in Outlook where it can’t be deleted, accessed, or even hidden from sight.
Thankfully, there’s a way to remove it.
As an administrator, open up ADSI Edit (which should be installed on the Exchange server, if not anywhere else), and navigate to the user who should own the mailbox. Right-click that user, and in the attributes list find “msExchDelegateListLink”. Edit this value, removing anyone who should no longer have access to the mailbox.
Once deleted, OK the editor and properties windows. The user (with the “ghost” mailbox) can now close and reopen Outlook. After a few minutes, if not immediately, the extra mailbox will magically vanish.
what is the path to “navigate to the user”?
In ADSI Edit, right-click ADSI Edit in the left pane and choose “Connect to:”. Connect to your domain controller (or “default naming context” if that’s that’s an option) and click OK.
You should now get a tree in the left pane that mirrors your Active Directory layout. The user will be in there.