What is divestiture migration?
Also known as
Definition
In a divestiture, part of an organization is separated and moved into a new or different Microsoft 365 environment. That means deciding which users go, which content moves, which shared workspaces get split, and what access to the parent tenant needs to be removed after separation.
Divestitures usually have a legal deadline, often external parties with visibility into the process, and strict rules about what the carved-out entity is and isn't allowed to take. Content that was shared between parent and child before the separation has to be audited and divided.
Example: A company sells one of its business units to another organization. The 2,000 employees in that unit need to move from the parent company's Microsoft 365 tenant into the new owner's tenant. Their emails, files, Teams channels, and SharePoint sites have to move with them. Access to the parent's content has to be cut off. And it all has to happen by the deal's close date.
Why it matters
A divestiture migration has a legal deadline, a defined separation boundary, and usually a new organization on the other side watching how it goes. Getting it wrong has consequences.
- Business continuity: The people who moved to the new organization need their email, files, and collaboration tools on day one.
- Separation: When a business unit is sold, its data and access have to move with it. Microsoft 365 doesn't enforce the business boundary automatically.
- Liability: Access that isn't revoked after the deal closes is a risk for both sides. Lingering connections between the two tenants create legal and security exposure.
Commonly confused with: Tenant consolidation
Consolidation brings multiple tenants into one. A divestiture splits one tenant into two. They use similar cross-tenant migration mechanics, but the direction, the scope decisions, and the business stakes are different.
What we see out there
Users need access to both environments during the transition.
After partial migration begins, users still need access to shared content on the source tenant. Cutting off that access too early disrupts work. Leaving it open too long risks data boundary violations after the legal separation date.
Data in the source keeps changing right up to cutover.
The source environment stays live during migration. Users keep working, files keep changing. At cutover, the migrated content has to reflect the current state of the source, not where it was when the migration started.
Frequently asked questions
What data should move in a divestiture migration?
Only what the business separation rules say belongs to the carved-out entity. That means inventorying all content: mailboxes, OneDrive, SharePoint sites, Teams, and mapping each item to either the parent or the carved-out entity before migration begins. Shared content that doesn't clearly belong to one side needs a business decision: move it, duplicate it, or leave it with the parent. Don't migrate first and sort it out later.
