To perform a secure <a href="https://www.cloudbik.com/solutions/microsoft-365-tenant-migrations/" target="" title="">mailbox migration between Microsoft 365 tenants</a>, start with proper planning and user assessment. Ensure both tenants are configured with modern authentication, verified domains, and required licenses. Use a staged approach with initial migration followed by incremental syncs to avoid data loss and downtime.

Preserve mailbox data such as emails, folders, calendars, and permissions, and validate mail flow after cutover. For complex tenant-to-tenant mailbox migrations, services like CloudBik help automate the process securely while minimizing risk and business disruption.