Exchange Online Cross-Tenant Migration Improving

• Exchange Online customers are getting better tools for migrating mailboxes between tenants after mergers, acquisitions, and divestitures.
• Cross-tenant mailbox migration requires careful planning, scripting, and testing.
• Improvements in preview will simplify the process and reduce the risk of errors.
• Add-on licenses and an Enterprise Agreement are required.

New and planned admin tools will help migrate Exchange Online mailboxes between Exchange Online tenants. They will particularly benefit mergers, acquisitions, and divestitures in which both organizations are on Exchange Online. However, Exchange mailbox migration is complex, and companies might still need to rely on third-party tools to handle the complexities in the cross-tenant case.

Why Cross-Tenant Mailbox Migration?

Cross-tenant mailbox migration moves Exchange Online user mailboxes from a source tenant to a target tenant, without first exporting the mailboxes to an on-premises store. Organizations first transfer mail user information to the target tenant, then schedule batches of mailbox moves that copy each user’s mailbox to the target before deleting it from the source.