Cross-tenant Migration

Hi,

Microsoft’s native cross-tenant mailbox migration is suitable for moving your 15 users to a new Microsoft 365 tenant. You can manage migration batches in EAC, but the initial configuration must be completed using certain Exchange Online PowerShell commands.

First, configure the required application permissions, organization relationships, and migration endpoint. Set up destination accounts and validate licensing requirements using Microsoft’s official guidance.

The main challenge is transferring the COMPANY-B domain. You must remove it from the source tenant after clearing its dependencies before adding it to the new tenant. Develop a comprehensive migration strategy to minimize email disruptions and prevent sign-in issues.

Also, check mailbox permissions, archives, Outlook profiles, and DNS records. SharePoint, OneDrive, and Teams may require separate migration steps.

Alternatively, you can use the WholeClear Office 365 to Office 365 Migration Utility to migrate mailboxes between Microsoft 365 tenants while specifying folders and email date ranges. It offers a guided workflow for source and destination account authentication.