We migrated 500+ Entra ID objects, and every one carried an attribute mapping decision. Those decisions determined whether downstream systems recognized the migrated object or broke authentication.

Identity is a different category of work than the data migration running beside it. Engineers who confuse the two in project planning put milestone dates at risk.

Before cutover, we evaluated user accounts, group memberships, and service principals. Then we validated the trust relationships between those objects and their registrations at the destination.

Sequencing was the hard part. Identity had to move in step with both the server migration and the file server migration so permissions stayed valid through cutover. It could go wrong in two ways:

• Move an identity before its dependent server workload is reachable in the destination, and authentication fails.
• Move it after the content has cut over, and users hit a permissions gap between the content becoming accessible and the identity being able to authenticate.

App registrations added a surprise. The same applications were registered in both the source and destination tenants, with overlapping redirect URIs. We identified every affected registration, worked with the application owners, and validated authentication flows in the destination tenant before deactivating the source registrations.

Identity isn’t step one. It runs in parallel, and it decides whether everything else you migrate works when users try it.

In your last tenant-to-tenant move, did identity go before, with, or after content?

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