Mailbox Migration- One M365 tenant to Another M365 tenant

Abi 80 Reputation points

Dear Microsoft

We're in the midst of a merger and would like to migrate the mailbox, onedrive and sharepoint content from one M365 tenant to another M365 tenant. This is migration is one time only to migrate the mailboxes and onedrive contents. We will no longer have any partnership with the source tenant. So basically migrate the mailboxes and other stuff and close the connection with source tenant.

My question is

  1. Does removing migration end point and removing organization relationship as per this article is enough to get rid of the connection
  2. I was reading the FAQs from the above link and came across this (how does mail flow works after migration). I dont want to have a mailflow created with the source tenant. I dont need a cross-tenant mailflow. What should I do to Disable this ( Or not enable this at all) ?



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2 answers

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  1. Bruce Jing-MSFT 1,845 Reputation points Microsoft Vendor


    Thanks for posting your question in the Microsoft Q&A forum.

    Based on your questions, I will answer them in turn.

    1. Can I get rid of connections by deleting migration endpoints and organizational relationships?

    Delete Migration Endpoints: Migration endpoints are connection points used during the migration process. Once the migration is complete, you can delete the migration endpoint to ensure that there is no longer a connection to the source tenant.

    Deleting Organizational Relationships: Organizational Relationships are used to establish a trust relationship between two tenants in order to share resources. It is a good practice to delete an organizational relationship if there is no longer a need to share any resources with the source tenant.

    2. I don't need a cross-tenant mailflow. What should I do to Disable this ?

    According to Microsoft's official documentation, each migrated mailbox needs a properly configured source MailUser with a destination address to forward the mail received from the source tenant to the mailbox of the target tenant, so cross-tenant mailflow cannot be disabled for the time being.

    If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.

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  2. pradeep sharma 0 Reputation points

    You need to remove the migration endpoints and organization relationship after the migration completes. No need to configure any mail flow. For complete step by step procedure, you will require cross-tenant user data migration license. However, you can check out this guide for complete manual migration process.

    Free Guide: