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Note: This case is migrated from MSDN Exchange Server Development forum. Since Exchange Server Development forum mainly discuss issues about Exchange development, and non-developer Exchange has transitioned to Microsoft Q&A for support, we migrated this non-developer question manually to continue the discussion.
Hi there,
I have a quick question, our organization is planning to migrate from on-prem Exchange 2016 to Office365. My question here is that If we do a cutover migration, does that move or copy our data to Office365? In other people tutorials, I see that the mailboxes are copied to the destination. If that's the case, will I be able to route MX record to old server if anything goes wrong? as a part of Disaster Recovery?
Many thanks!!!
For cutover migration, yes, data will be copied to O365. In general, after changing the MX record and Autodiscover configuration, you can use the on-premises mailboxes. However, new data generated after the migration won't be available, we have to use pst files to export and import those items.
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LydiaZhou,
Thanks for your reply.
If thats the case, does that mean we can migrate the data onto the cloud from on-Prem few days before the MX change just to verify if the data is moved correctly and re-run the synchronize regularly to sync the changes? Once the data move is complete then change the routing in couple days?
What synchronization do you mean?
In general, yes, we change MX record after verifying the migration is done. Then we have to wait at least 72 hours for the email systems of your customers and partners to recognize the changed MX record. After that, we can delete the cutover migration batch.
You can check this for more details about the cutover migration steps: Migrate email using the Exchange cutover method.
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Just checking in to see if above information was helpful.
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Hi LydiaZhou-MSFT,
Sorry for the delayed response, the information was very helpful. Thank you!!!
It's great that you can get useful information here. If you don't mind, I will accept the reply as Answer. This will be easy for other community members to find the useful one.
Thanks for your understanding.
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