Microsoft 365 cross-tenant consolidation

Our summary

We are leading the consolidation of fourteen country tenants, and one entity on Google Workspace, into a single Microsoft 365 estate administered from one place.

The practice

Cross-tenant consolidation is the work we have done most often: seven programmes to date across international aid, public bodies, global business services and food manufacturing. Mergers, acquisitions, group restructures and public bodies being folded together all end at the same place: two or more Microsoft 365 tenants that have to become one.

The programme described here is the largest. Fourteen tenants had grown up independently across a global aid organisation, one per country entity, each with its own identity model and its own idea of what good looked like. One entity was not on Microsoft 365 at all. It ran Google Workspace.

What we did

We co-authored the migration strategy and solution design across identity, device management, Exchange Online, data, Teams Voice, Power Platform and Microsoft Fabric. We then led the SharePoint Online workstream, designing a hub-site model for each incoming entity and Entra ID group-based permissions with hub-level sharing controls, so the whole estate is administered from one place.

The Power Platform framework covered canvas and model-driven apps, cloud and desktop flows, Power BI, Forms and Dataverse, with DLP policies, environment provisioning and migration sequencing defined up front. We moved Fabric workloads using Git integration for controlled item movement, and kept gateway configuration and refresh schedules running throughout.

How we reduced the risk

We chose AvePoint Fly for content and LinkFixer Advanced for the links every migration breaks, then validated both in pilot waves for two smaller country entities before the larger ones move.

Every workstream has a runbook: SharePoint Online, Power Platform, Power BI, Fabric, identity, mail and voice. Those runbooks stay with the client after we leave.

Where it stands

The programme is in delivery. Migration tooling has been validated through two pilot waves, and the design covers identity, devices, mail, data, Teams Voice, Power Platform and Fabric for all fourteen tenants and the Google Workspace entity.

Teams Voice and calling are designed for four countries. We will add the final figures to this case study when the last entity has moved.