Move on-premises Exchange Mailboxes mailboxes to Exchange Online (Office 365)
- Open the Exchange Admin Center, and then navigate to Office 365 > Recipients > Migration.
- Click Add , and then select Migrate to Exchange Online.
- On the Select a migration type page, select Remote move migration and then click Next.
- On the Select the users page, click Add and select the on-premises users to move to Office 365 and click Add and then click OK. Click Next.
- On the Confirm the migration endpoint page, verify that the FDQN of your on-premises Exchange server is listed when the wizard confirms the migration endpoint. For example, “mail.enterpriseit.co”. Click Next.
Note: The MRSProxy service on the Exchange servers automatically throttles the mailbox move requests when you select multiple mailboxes to move to Exchange Online. The total time to complete the mailbox move depends on the total number of mailboxes selected, the size of the mailboxes, and the configuration of the MRSProxy. To learn more about customizing the MRSProxy, see Message throttling.
- On the Move configuration page, enter a name for the migration batch in the New migration batch name text field. Use the down arrow to select the Target delivery domain for the mailboxes that are migrating to Office 365. In most hybrid deployments, this is the primary SMTP domain used for the Exchange Online organization mailboxes. For example, contoso.mail.onmicrosoft.com. Verify that the Move primary mailbox along with archive mailbox option is selected, and then click Next.
- On the Start the batch page, select at least one recipient to receive the batch complete report. Verify that the Automatically start the batch option is selected, and then select the Automatically complete the migration batch check box. Click New.