We accidentally deleted a user from AD who has an Exchange mailbox. The mailbox remained intact. We subsequently recreated the user in AD, but we are having issues with some third party software, SIDs etc. We therefore created a new, unique AD account for the same user with a differing alias, User Name etc.

We want to use this new account, and therefore need to associate the Exchange mailbox from the old account, to the new account.

I've seen that you can delete the account from AD (which orphans the mailbox), run the Exchange Cleanup Agent to mark the mailbox as orphaned, go into Disconnected Mailboxes, right click and Connect.

Deleting the original AD account is not an option so this is not possible.

We've updated the User Principal Name in the mailbox and everything in AD and Exchange suggests that when the user logs in under the new account, Outlook should simply open up to her original mailbox.

Any insight is appreciated.

  • 4
    Which version of Exchange? May 1, 2012 at 21:47

3 Answers 3


At least in Exchange 2010, you can use the disable-mailbox cmdlet in the exchange shell:

Disable-Mailbox -Identity [email protected]

The mailbox will immediately show up as a disconnected mailbox and can be connected to any account that does not have a mailbox associated with it. The AD account is not affected (other than to have its exchange properties removed, of course).


You could try connecting the mailbox to some other user and then connecting it back to the user you re-created in order to force it to resolve the SID again.

  • Falcon, This would not be possible because in order to connect the mailbox to user B, it would have to disconnect from user A. In order for the mailbox to disconnect from A (from my current understanding), you'd either have to do a soft delete (by clicking Remove on the mailbox) which deletes the AD account, or actually delete the AD account, run the Clean-Maiboxdatabase cmdlet then connect the mailbox to user A. Both situations result in the deletion of the AD account, which we cannot have. May 2, 2012 at 13:25

Have you tried using the import / export mailbox function in in shell? It might be able to assist you here- http://www.msexchange.org/articles_tutorials/exchange-server-2010/management-administration/exporting-importing-mailboxes-exchange-server-2010.html

  • 1
    Import-Mailbox cmdlet would only import the emails, it would not import any of the custom settings such as the 20+ recurring reminders that the user has set up or the user's calendar. It would also dump all of the emails out of their current custom folders and import have them as a large (very large in this case) disorganized mass of messages. While it does give the new user their old messages, it wipes out everything else. May 2, 2012 at 14:13

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