Exchange 2010 Move all mailboxes to a new mailbox database

PROBLEM :

This mailbox database contains one or more mailboxes, mailbox plans, archive mailboxes, or arbitration mailboxes.

SOLUTION :

The trick to seeing the Arbitration Mailboxes is to Set-AdServerSettings:

Set-AdServerSettings -ViewEntireForest $True

Run the Get-Mailbox command to see if there are any Arbitration Mailboxes :

Get-Mailbox -database mbox1 -arbitration | Format-Table name,servername
Name                                                                                         ServerName
—-                                                                                              ————–
SystemMailbox{1f05a927-855a-4565-9eb5-64a2db420387}         mail
SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}         mail
FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042             mail

Now you see the three Arbitration Mailboxes. Lets go ahead and move them to the new mailbox database :

New-MoveRequest -Identity "SystemMailbox{1f05a927-855a-4565-9eb5-64a2db420387}"
New-MoveRequest -Identity "SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}"
New-MoveRequest -Identity "FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042"

You can see the status of the move requests with the Get-MoveRequest command.

Once the move requests are completed, they must be removed :

Get-MoveRequest -SourceDataBase "mbox1" | Remove-MoveRequest
Confirm
 Are you sure you want to perform this action?
 Removing completed move request "xxxxxxxxxxx".
 [Y] Yes  [A] Yes to All  [N] No  [L] No to All  [?] Help (default is "Y"): a