The main steps you perform for a cutover migration are shown in the following illustration.
- The administrator communicates upcoming changes to users and verifies domain ownership with the domain registrar.
- The administrator prepares the servers for a cutover migration and creates empty mail-enabled security groups in Office 365.
- The administrator connects Office 365 to the on-premises email system (this is called creating a migration endpoint).
- The administrator migrates the mailboxes and then verifies the migration.
- Grant Office 365 licences to your users.
- The administrator configures the domain to begin routing email directly to Office 365.
- The administrator verifies that routing has changed, and then deletes the cutover migration batch.
- The administrator completes post-migration tasks in Office 365 (assigns licenses to users and creates an Autodiscover Domain Name System (DNS) record), and optionally decommissions the on-premises Exchange servers.
The administrator sends a welcome letter to users to tell them about Office 365 and to describe how to sign in to their new mailboxes.