When to do the domain cutover when migrating from GSuite to Microsoft 365

Question

I am performing a migration from GSuite to Microsoft 365 using the automated tool in EAC in Exchange Online. I understand that when the migration is done, the status is set as Synced and then I would need to Click the Complete button to complete the migration. The complete button will do a final sync to migrate the last items. When the migration is finished and before clicking the Complete button, is this the window to the migrate the domain from the environment to M365?

If not, when do I need to do the cutover?

Answer 1

Hi,

Thank you for sharing your question. I understand how important timing is in this process and how confusing it can be when you see the migration status as “Synced” and wonder if that’s the right moment to move the domain. Let’s clarify why this happens and what the best practice is.

When using the Exchange Admin Center migration tool, the “Synced” status means that the initial batch migration has completed and mailboxes are being synchronized continuously. Clicking Complete will perform a final sync and stop the migration batch. The domain cutover—changing MX records to point to Microsoft 365 should happen before you click Complete but only after you confirm that all mailboxes are syncing correctly and users can access their migrated data in Microsoft 365. This ensures that new incoming mail flows directly to Microsoft 365 while the final sync captures any remaining items from GSuite.

To avoid mail delivery issues, update your DNS MX records during this window when the batch is in “Synced” state and before completing the migration. After the MX change propagates and mail is flowing to Microsoft 365, you can safely click Complete to finalize the migration.

 

I hope this helps.

 

Best Regards,

Noel

Answer 2

The domain cutover from GSuite to Microsoft 365 should be done after you have completed the migration process. Specifically, you should wait until the migration batch status is set to Synced and you have confirmed that all necessary data has been migrated. Once you click the Complete button to finalize the migration, you can then switch your primary MX record to point to Microsoft 365 or Office 365. This ensures that all email is routed correctly to the new environment. It is important to wait at least 72 hours after changing the MX record to ensure that the email systems recognize the change before stopping synchronization with GSuite.

Therefore, the cutover should occur after the migration batch is completed and the MX record has been updated accordingly.