How to delete the default database in Exchange 2010

You’ll probably want to delete the default database that is created when you build a new Exchange 2010 server. So you’ve moved all the mailboxes that you can see to another database. And then you’ll remove the database.
But if you do try, then you’ll get the following message:

Key Error Messages

The mailbox database ‘Mailbox Database ’ cannot be deleted.
This mailbox database contains one or more mailboxes or arbitration mailboxes.

This is because there are hidden mailboxes.

Here’s how to find them, move them and then remove the database.
Find them

You’ll need to use the EMS, The Exchange Management Shell, for this.

  1. Use the Get-Mailbox – Database command as I have in the image below:
  2. You’ll see the SystemMailbox, as listed in the image above. You may see more than one mailbox in your listing.
  3. Copy the mailbox name(s) to notepad.

Move them

Still within the EMS…

  1. Use the New-MoveRequest command as seen in the image below, pasting back in the mailbox name you copied in the Find them steps above.
  2. If you need to move your arbitration\system mailboxes to a specific database, you could instead use the New-MoveRequest command but add the following switch:
    -TargetDatabase “Database_Name” as shown in the image below.
  3. When you do your move-request, Exchange will queue the move. In the background, Exchange 2010 will perform the move, just as it does for a move performed from EMC.
  4. Repeat step 1 or 2 if you have more mailboxes like this to move.
  5. Use Get-MoveRequest to check that the move has worked:

    You could do this within Move Request in the Exchange Management Console GUI, but you wouldn’t be able to confirm which database the mailbox had moved to.

Remove the database

Remove the database in the usual way in the Exchange Management Console.
I hope this has helped you.