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Summary: Exchange Server administrators often face issues with arbitration mailboxes, especially after migrating to on-premises Exchange 2013 or later. These problems result in Event log errors, indicating corrupted or missing mailboxes. This article explains the functions of essential arbitration mailboxes and provides a step-by-step guide to recreating them, ensuring a smoother migration experience. Key prerequisites and commands in Exchange Management Shell are detailed to resolve these issues effectively.

Exchange Server administrators frequently encounter various issues while managing the Exchange environment. One common problem arises after migrating to on-premises Exchange 2013 or later versions, where administrators often encounter Event log errors that reference arbitration mailboxes. These errors typically indicate that these mailboxes are either corrupted or missing.

Arbitration Mailboxes

Arbitration mailboxes, also known as Exchange system mailboxes, serve critical roles in overseeing local system data and managing message workflows. Below, we outline the functions of the five essential arbitration mailboxes:

  • Microsoft Exchange Federation Mailbox (FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042)
    Used to store Exchange data for maintaining federation between Exchange organizations.
  • Microsoft Exchange Migration (Migration.8f3e7716-2011-43e4-96b1-aba62d229136)
    For storing Exchange migration data services in batch migration
  • Microsoft Exchange Approval Assistant (SystemMailbox{1f05a927-XXXX-XXXX-XXXX-XXXXXXXXXXXX})
    Used in the Exchange approval framework (for recipient moderation and auto group approval requests).
  • Microsoft Exchange (SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c})
    For creating Offline Address Books
  • Microsoft Exchange (SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9})
    For locating messages specified by some matches through e-Discovery feature.

Now, when facing issues concerning arbitration mailboxes, such as corruption or missing mailboxes after migrating to on-premises Exchange, we have the solution of recreating these mailboxes. In this discussion, we will delve into the comprehensive procedure, including the necessary prerequisites.

  • Exchange administrator or user must be assigned Recipient Provisioning Permissions.
  • Membership in the Enterprise Admins security group.
    1. In case arbitration mailboxes are corrupted, you need to delete all User Types from Active Directory user accounts
      Note: Run Get-Mailbox-Arbitration to see if the arbitration mailboxes are removed.
    2. In case arbitration mailboxes are missing or deleted as in above point, you must run the following command in Windows Command Prompt to create mailboxes again
      <Drive>: \Setup /preparead /IAcceptExchangeServerLicenseTerms
Enabling Arbitration Mailboxes

After recreating mailboxes, you need to enable them with the following commands in Exchange Management Shell.

  • Microsoft Exchange Federation Mailbox
    Enable-Mailbox -Arbitration -Identity “FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042”
  • Microsoft Exchange Approval Assistant Mailbox
    Get-User | Where-Object {$_.Name -like “SystemMailbox{1f05a927-7709-4e35-9dbe-d0f608fb781a}”} | Enable-Mailbox -Arbitration
  • Microsoft Exchange Migration Mailbox
    Enable-Mailbox -Arbitration -Identity “Migration.8f3e7716-2011-43e4-96b1-aba62d229136”
  • Microsoft Exchange Discovery System Mailbox
    Enable-Mailbox -Identity “SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}” -Arbitration
  • Microsoft Exchange Organization Mailboxes for OABs
    Enable-Mailbox -Arbitration -Identity “SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}”

You can verify the successful recreation of the arbitration mailboxes by the execution of this command again with ADServer settings.

Set-ADServerSettings -ViewEntireForest $true; Get-Mailbox -Arbitration | Format-Table Name,DisplayName

So, now you would find relief from the Event logs errors or other issues like missing, corrupted, or deleted arbitration mailboxes while DAGs are corrupted and recreated.


During the migration process, it’s possible to encounter missing or corrupted arbitration or system mailboxes in Exchange, which can lead to various problems, including restrictions on the local movement of mailboxes. In this context, we’ve outlined a manual solution that involves recreating the Exchange arbitration mailboxes by utilizing Exchange Management Shell cmdlets. This approach aims to address and rectify such issues for a smoother migration experience.

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