How to recreate missing arbitration mailboxes in Exchange Server?

Read time 3 minutes

Exchange Server administrators experience one or other issues in the Exchange environment as part of its management. For example, after migration to on-premises Exchange 2013 or later versions, an issue is commonly observed where Event log errors are received with the mention of arbitration mailboxes. It means these mailboxes are either in a corrupt state or are missing.

Arbitration mailboxes

Arbitration mailboxes are also called as Exchange system mailboxes whose functions are related to local system data and message workflow management.

The five arbitration mailboxes with their functionalities are provided below:

• 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.

So, now, to deal with the errors related to arbitration mailboxes like corruption or missing mailboxes after migrating to on-premises Exchange, we have the option to recreate these mailboxes. We would be discussing the complete method along with pre-requirements here.

Pre-requirements

• 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.

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.

Conclusion

Arbitration or system mailboxes in Exchange could be missing or corrupted during migration, causing many issues like restriction in local movement of mailboxes. We have discussed the manual solution for recreating the Exchange arbitration mailboxes using Exchange Management Shell cmdlets.