Exchange13/16 recovers lost or damaged migration mailboxes

After Exchange2013, migration operations for mailboxes rely on the system's Migrate Mailbox role. If this role is damaged or lost, it will definitely affect the mailbox migration, so we need to have a way to repair this role.

What is a migration mailbox?

When introducing or deploying Exchange2013 or Exchange2016 as a whole in an Exchange organization, we notice that there is one more user in AD's Users container, Migration.8f3e7716-2011- 43e4 -96b1-aba 62d229136. It is similar to the discovery mailbox and arbitration mailbox, which belong to the system mailbox, not the user mailbox. It is responsible for mailbox migration.

You can run Get-mailbox -Arbitration to view the mailbox.

2. Impact of Migrating Mailbox Loss

After the mailbox is lost, you will not be able to perform the mailbox migration in Exchange admin center, and the error is shown in the following figure.

3 How to recover migrated mailboxes

To resolve this issue, perform the following steps:

Start the Active Directory Users and Computers snap-in

Click Users and verify that the following accounts exist:

Note: If you have this account in the Users container, go to step 4.

3. Run the following cmdlet:

Setup /preparead /IAcceptExchangeServerLicenseTerms

4. Run the following cmdlet: Enable Mailbox-Arbitration-Identity "Migration.8f3e7716-2011-43e4-96b1-aba62d229136"

Set-Mailbox "Migration.8f3e7716-2011-43e4-96b1-aba62d229136" -Arbitration -Management:$true