We're in the process of upgrading our servers from Exchange 2010 to Exchange 2013. During the installation of Exchange 2013 some things went wrong as why it could not be fully installed. It stopped at step 7 of 15 or so. After reinstalling the server and doing a disaster recovery, Exchange 2013 installed successfully (well, 'successfully' till now).

As we configured the new Exchange installation, we discovered that the Mailbox Database was unmounted. We discovered the Mailbox Database files weren't created: there are no transaction logs nor is there an .edb file at the path the database should be stored. I guess this is due to the failed installation which we recovered using Disaster Recovery.

Is there a way to somehow re-create this database, recover it or just completely remove Exchange 2013 from the server and AD so we can just start over again and do it right this time (uninstalling is impossible at the moment cause it thinks there are still mailboxes (Migration Mailbox, that is) being stored in the missing database, which we can't delete cause then it errors out saying the database can't be mounted)?

  • Wouldn't it be easier to restore from backups and go from there? Are you doing this on your live environment without ever having tested it before? – gparent Jun 21 '13 at 19:42
  • We have tested this but the error we encountered installing Exchange 2013 was unexpected - during testing everything went alright. The new server is a clean server which isn't in production at the moment. All production servers (2010) are running just fine now, nothing wrong with them :-) – Robbietjuh Jun 21 '13 at 19:44

I would just wipe the server and start over again. Otherwise you're in for a long day (and calls with Microsoft) trying to get Exchange to behave.


Can you disable the mailbox and try again? I was able to disable the mailbox on my install with the database it resides in dismounted.

Get-Mailbox -Arbitration -Database [name_of_missing_db] | ft name
Disable-Mailbox Migration.[guid] -Arbitration

Make sure to record the actual name (or find it in the Users container in ADUC). After you get a mailbox database online, you can run:

Enable-Mailbox Migration.[guid] -Arbitration
Set-Mailbox Migration.[guid] -Arbitration -ProhibitSendQuota '300 MB'

Here's a helpful link that goes through the process with other system mailboxes:


  • Unfortunately I can't test this anymore now as we decided to just nuke the machine and start over with a fresh install. However, we were missing the entire database - not just a single mailbox. I'm not sure as I can't replicate right now, but it looks like you're just recreating the mailboxes - not the entire database. Thanks for your answer and effort, though! – Robbietjuh Jun 21 '13 at 23:04
  • You said it was the existence of the mailbox preventing you from proceeding with the uninstall. Are you also rebuilding AD? If not, it's still there. You'll have to use adsiedit to remove it from Configuration > Services > Microsoft Exchange > ORG_NAME > Administrative Groups > Exchange Administrative Group (FYDIBOHF23SPDLT) > Databases. When you delete it here, it's deleted from Exchange. That will leave you with orphaned system mailboxes though, for which you'll have to follow the instructions above to recreate. – Jeremy Lyons Jun 21 '13 at 23:10

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