Exchange move arbitration mailbox

When you deploy a new Exchange server the setup routine automatically creates a default database with a name in the form Mailbox Database <GUID> one of the first action you want to take after the installation is remove this default database but if you try to do so you’ll receive an error similar the following:

Arbitration Mailbox error

As you can see in the screenshot I cannot remove the default database because, according to Exchange Management Shell, the database is not empty even if running a Get-Mailbox database “Mailbox Database ” does not return any result, what the EMS is complaining about is the Arbitration Mailbox which you need to move before being able to remove the database itself.

An Arbitration Mailbox in Exchange 2010+ is used to store organization-wide data like metadata for eDiscovery searches, administrator logs or even Unified Message data like dial plans, custom greetings etc.

As already said if you issue a Get-Mailbox database “Mailbox Database ” command the arbitration will not be displayed, to show arbitration mailbox you can use one of the following cmdlets:

# Method 1 explicitly display Arbitration mailbox information 

Get-Mailbox -Arbitration   | select NAme, Alias, ServerNAme, Database | ft

# Output of the command will be similar to

Name                          Alias                         ServerName                    Database
----                          -----                         ----------                    --------
SystemMailbox{1f05a927-198... SystemMailbox{1f05a927-198... srv-ex2k10-mb01               Mailbox Database 0971754664
SystemMailbox{e0dc1c29-89c... SystemMailbox{e0dc1c29-89c... srv-ex2k10-mb01               Mailbox Database 0971754664
FederatedEmail.4c1f4d8b-81... FederatedEmail.4c1f4d8b-81... srv-ex2k10-mb01               Mailbox Database 0971754664

# Method 2 display arbitration mailbox information for a specific database

Get-Mailbox -Database "Mailbox Database " -Arbitration 

# Output of the command will be similar to

Name                      Alias                ServerName       ProhibitSendQuota
----                      -----                ----------       -----------------
SystemMailbox{1f05a927... SystemMailbox{1f0... srv-ex2k10-mb01  unlimited
SystemMailbox{e0dc1c29... SystemMailbox{e0d... srv-ex2k10-mb01  unlimited
FederatedEmail.4c1f4d8... FederatedEmail.4c... srv-ex2k10-mb01  1 MB (1,048,576 bytes)

As you can see it does not matter which form of the cmdlet you’ll use as result will be the same, now that we know the database is actually not empty we need to move the arbitration mailbox to another mailbox database which can easily be done with the following cmdlet:

# Move Arbitration mailbox to a new mailbox database

Get-Mailbox -Arbitration | New-MoveRequest -Targetdatabase "DB01_Standard"  -BatchName "Move Arbitration Mailbox"

# Arbitration mailbox move is confirmed
DisplayName               Status                    TotalMailboxSize          TotalArchiveSize         PercentComplete
-----------               ------                    ----------------          ----------------         ---------------
Microsoft Exchange App... Queued                    0 B (0 bytes)                                      0
Microsoft Exchange        Queued                    33.55 KB (34,352 bytes)                            0
Microsoft Exchange Fed... Queued                    0 B (0 bytes)                                      0

As with any other move request you can verify the arbitration mailbox move with a command similar to:

# Verify arbitration mailbox move status

Get-MoveRequest | Get-MoveRequestStatistics

# Output of complete arbitration mailbox move

DisplayName               Status                    TotalMailboxSize          TotalArchiveSize         PercentComplete
-----------               ------                    ----------------          ----------------         ---------------
Microsoft Exchange App... Completed                 0 B (0 bytes)                                      100
Microsoft Exchange        Completed                 35.86 KB (36,720 bytes)                            100
Microsoft Exchange Fed... Completed                 0 B (0 bytes)                                      100

Once the arbitration mailbox move is complete you can dismount the mailbox database and delete it without any issue.

I hope the post will prove useful and you will take a second to leave a comment and share it.


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