How to find and move the Exchange Arbitration Mailboxes

The Exchange System (Arbitration) Mailboxes, like ‘Discovery Search’ are created on the first Exchange server installed in the organization. If you need to remove a database or uninstall Exchange you will need to move the arbitration mailboxes to a different database or different server, respectively.

Command to search all databases for the arbitration mailboxes:
get-mailboxdatabase | Get-Mailbox -Arbitration |ft name,database,servername

Here is the command to determine if arbitration mailboxes are contained in a specific database:
Get-Mailbox –Database “Mailbox Database 1” –arbitration

Note: if your Exchange server is in a child domain it will appear that the arbitration mailboxes are missing. Use this command so that your get-mailbox commands will search all domains:
Set-ADServerSettings -ViewEntireForest:$true

Command to move all the arbitration mailboxes in the specified database to a new target database:

Get-Mailbox –Database “Mailbox Database 1” –arbitration | New-MoveRequest –TargetDatabase “Mailbox Database 2”

Check the status of the move and verify it has completed:
Get-MoveRequest

Note: If you are trying to uninstall one of your Exchange servers or remove a database and you haven’t moved the Arbitration mailboxes you may receive an error similar to the following: “This mailbox database contains one or more mailboxes, mailbox plans, archive mailboxes, or arbitration mailboxes.”

10 thoughts on “How to find and move the Exchange Arbitration Mailboxes”

John M May 31, 2019 at 11:44 am

Question? Do the arbitration mailboxes exist in every copy of a given database? For instance, we have one Exchange 2013 site in two physical locations. We are decommissioning one of the physical locations yest when I do a get-mailboxdatabase | Get-Mailbox -Arbitration |ft name,database,servername it shows the database on one of the servers that is in the to be decommissioned location. But our other physical location has the active copy of that database.

Do I need to move the mailboxes to a different DB before decommissioning or will removing the DB copies from the server and uninstalling Exchange be all I need to do?

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Chris Post authorJune 22, 2020 at 10:05 pm

I believe arbitration mailboxes exist on a per server basis and live in one of the databases on the server, they may actually be on a per exchange organization basis. You want to move the arbitration mailboxes to a different database before decommissioning a database.

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