Direct tenant-to-tenant mailbox migration with email, calendar, and contacts.
Related topics
mailbox migration
email migration
exchange migration
tenant migration
mail transfer
About this tool
The Mailbox Migration tool enables direct tenant-to-tenant migration of Exchange Online mailboxes. Migrate email messages, calendar events, and contacts without intermediate staging.
Zero-knowledge architecture ensures mail content never passes through third-party servers. Direct Graph API transfers between source and target mailboxes for complete privacy and security.
Includes folder structure preservation, attachment handling, and calendar invitation re-linking in the target tenant.
Key features
Direct mailbox transfer
Email message migration
Calendar event migration
Contact migration
Folder structure preservation
Attachment handling
Zero-knowledge transfer
Progress monitoring
Use cases
Tenant migration. Migrate mailboxes without staging servers
User migration. Move individual users between tenants
Post-acquisition integration. Consolidate mailboxes after merger
Requires a paid edition (migration). The Suite bundle includes this tool alongside every other capability in the catalogue.
Limitations & out-of-scope
Unlike Chat History Export and Shared Mailbox Migration, this tool does not split source and target into two separately consented OAuth apps — Mail.ReadWrite and Calendars.ReadWrite operate across both mailboxes under the same authorization, so the operator's consent step covers both ends in one grant. Throughput is bound by Microsoft Graph's own per-app throttling on both mailboxes involved, and folder structures that don't already exist on the target are created to match the source, not merged with existing target folders of the same name.