There are various methods to migrate mailboxes from on-premises Exchange Server to an Office 365 tenant. These include Cutover, Staged, Minimal Hybrid, and Full Hybrid. In a Hybrid environment, both Exchange on-premises and Exchange Online work as one. This method is ideal if you don’t want any interruption during the migration of data. However, sometimes, when trying to move a mailbox or mailboxes from on-premises to Exchange online, you might receive the following error messages (or similar):
Error: UserAlreadyBeingMigratedException: The user ’mailbox’ already has a pending request. Please remove the existing request and resume the current batch or start a new batch for this user. –> Mailbox ’Name’ is already being moved to ’office 365 database’.
Error: MigrationPermanentException: The onboarding move could not be created because user ’mailbox’ is already being moved. –> The onboarding move could not be created because user ’mailbox’ is already being moved.
However, if there is a previous move which was in process or has failed/stuck, then you will get a similar error.
The error “SourceMailboxAlreadyBeingMovedPermanentException” would be different, depending on the following scenarios:
- If you receive the error message, “Mailbox ‘Name’ is already being moved to ‘<office 365 database>.”, it means that you had a move request done on a user. This will not allow you to move it. This happens when the user has an active or an orphaned move request in Exchange Online.
- If you receive the error message, “The onboarding move could not be created because user ‘Name’ is already being moved”, it means that there is already an active or orphaned move request in your Exchange Server for the specific user.
Steps to Fix the SourceMailboxAlreadyBeingMovedPermanentException Error
Step 1: First, you need to identify if there are actual move requests for the user specified in the error. For this, you need to run the Get-MoveRequest command on both Exchange Server and Exchange Online.
For the local Exchange Server, open the Exchange Management Shell (EMS) and run the following command:
Get-MoveRequest -Identity 'user@contoso.com'
For Office 365, you need to run the same command by using the Exchange Online PowerShell.
In case you don’t know the identity of the user, you can run the command alone. It will get you all the move requests in Exchange Server or Exchange Online.
Step 2: Next, you need to verify and delete the move requests so that you can re-run the new move requests. You can verify the move request by checking the status. The status would be either completed or failed. You will need to remove the request manually to re-run a move. For this, you can use the Remove-MoveRequest command.
If the move of that user is part of a migration batch, you need to remove the whole batch or the user from the batch. Once done, this will remove the move request of the user.
If the error persists, then you need to remove the request manually for the user from the on-premises Active Directory Schema. For this operation, you need to use the ADSI Edit application. Here are the steps to do so:
Note: You need to keep in mind that when using ADSI Edit or Active Directory Attributes, you are editing the Active Directory Schema. Any changes or mistakes can have catastrophic repercussions on your Active Directory, Exchange Server, and other applications which are dependent on your Active Directory.
- Open the Active Directory Users and Computers from your Domain Controller and locate the affected user.
- Right-click on the user and click on Properties.
- Click on the Attribute Editor.
- Locate the attributes which start with msExchMailboxMove.
- If any attributes are populated, you need to clear them off. This usually happens when there was a move request and it hasn’t cleared the attributes.
Note: There is no way to clear all the users at once or automatically through the GUI. So, this must be done manually.
Conclusion
The error “SourceMailboxAlreadyBeingMovedPermanentException” can occur when migrating mailboxes from an on-premises Exchange Server to Exchange Online (Microsoft 365) in a hybrid environment. As discussed earlier, there are several steps you can take to resolve this issue. However, if the problem persists, you can use a professional migration tool such as Stellar Migrator for Exchange. This advanced application simplifies the mailbox migration process by allowing direct migration from on-premises Exchange to Office 365 or another Exchange Server with minimal downtime. It supports automated mailbox mapping, parallel and batch migrations, pre- and post-migration analysis, and priority-based transfers. Stellar Migrator for Exchange ensures a secure, efficient, and seamless transition of mailboxes across Exchange environments.
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