Restoring a deleted Exchange 2010 mailbox from PowerShell

By Chris Blackburn

In our hosted Exchange 2010 SP1 environment we have to administer the environment via PowerShell, versus using the traditional Exchange Management Console (EMC) – one of the lovely limitations of using /hosting mode. Surprisingly, after almost a year of being in production this one had never come up until just yesterday: a user had been deleted (via Exchange Control Panel, which you can still thankfully use for end-user management) and their mailbox still sat on the server thanks to deleted mailbox retention. But how would I approach recovery

First, I needed to see what was out there from a recovery perspective. Thanks to Mike Pfeiffer’s blog post I was able to add his Get-DisconnectedMailbox function to my PowerShell profile by using the notepad $profile command. After a quick restart of the Exchange Management Shell (EMS) I ran the command and it easily gave me a list of all disconnected mailboxes across all of the databases, and I was able to confirm that the user’s mailbox was still there.

So the next challenge was, how can I do this all from PowerShell?

Hosting mode brings its own set of challenges, namely the lack of the familiarity a “point-and-click” environment provides. So after some digging I ran across’s article on how to reconnect a deleted mailbox. Now while in the past I’ve been able to create a new AD user and reconnect the mailbox, to my delight it says that I can create a new restore request against a deleted mailbox against an active mailbox – and both can have the same name!

So I proceeded to run this wonderful command:

New-MailboxRestoreRequest -SourceDatabase Datastore1 -SourceStoreMailbox “End User” -TargetMailbox “End User”

But it failed with an error saying that the DN (distinguished name) did not match, and to use the AllowLegacyDNMismatch switch. Once I added it to the end of this command:

New-MailboxRestoreRequest -SourceDatabase Datastore1 -SourceStoreMailbox “End User” -TargetMailbox “End User” -AllowLegacyDNMismatch

The process started successfully, and after 10 minutes was completed. I logged into the user’s mailbox, and sure enough not only were the emails there but I noticed it even restored some of the shared mailbox folders. Impressive!

1 Comment Leave a comment

  1. Thanks, i was stucked in the same parameter “allowedDNMistmatch” and looks like it works!

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