What are Arbitration Mailboxes used for?

Arbitration Mailboxes were first introduced in Exchange 2010, but many administrators still do not fully understand what each arbitration mailbox is used for. In Exchange 2010 there were three arbitration mailboxes and in Exchange 2013 two new ones were introduced (2016 has the same as 2013):



SystemMailbox{1f05a927-xxxx-xxxx-xxxx-xxxxxxxxxxxx} moderates messages, i.e., it is used for managing approval workflow. For example, an arbitration mailbox is used for handling moderated recipients and distribution group membership approval. The display name for this account is Microsoft Exchange Approval Assistant and is available since Exchange 2010.

SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c} is used in the Offline Address Book (OAB) generation process. This arbitration mailbox, with persisted capability of OrganizationCapabilityOABGen, is called an Organization Mailbox. Administrators can create additional Organization Mailboxes for fault tolerance or for serving users in a geographically disbursed Exchange deployment. As such, to list the arbitration mailboxes with persisted capability of OABGen, user the following cmdlet: Get-Mailbox -Arbitration | Where {$_.PersistedCapabilities -match “oab”}. This mailbox is new in Exchange 2013.

SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9} holds administrator audit log reports and stores in-place e-discovery search metadata. The display name for this account is Microsoft Exchange. This mailbox is available since Exchange 2010.

FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042 is used for federation between different Exchange organizations and is available since Exchange 2010. Its display name is Microsoft Exchange Federation Mailbox.

Migration.8f3e7716-2011-43e4-96b1-aba62d229136, new in Exchange 2013, holds details of mailboxes being moved in migration batches.


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1 thought on “What are Arbitration Mailboxes used for?”

  1. Any update for the Exchange 2019 System Mailboxes? I noticed I have 2x in 2019:

    DisplayName : E4E Encryption Store – Active
    Name : SystemMailbox{D0E409A0-AF9B-4720-92FE-AAC869B0D201}

    DisplayName : Microsoft Exchange
    Name : SystemMailbox{2CE34405-31BE-455D-89D7-A7C7DA7A0DAA}

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