Tenant to tenant migration

Both Google Workspace and Microsoft 365 will only verify a given domain in one tenant. That single fact shapes every merge. You cannot gradually move addresses from one estate to another while both claim the domain; you run coexistence, then you move the domain in one scheduled event, then you finish.

Everything else in the project is arranged around that moment. Mail is pre-synced, calendars are made visible across both estates, directories are synchronised for lookup, and the domain move becomes a controlled cutover rather than a migration in itself.

Two organisations merging produce duplicate names with predictable regularity, and someone always already has an account in both estates, usually a director or a shared finance address. The naming convention for the merged estate has to be agreed before any account is created, because renaming after the fact breaks every reference to the old address.

We produce a full collision report in discovery: duplicate display names, duplicate addresses, aliases that would collide after the domain move, and groups whose membership overlaps. Each one gets a decision and an owner before any data moves.

For a few weeks the two organisations need to behave like one while remaining technically separate. That means mail routing between estates, free-busy calendar lookup across the boundary, and a shared directory for address book lookups. None of it is permanent and all of it is dismantled after the domain move.

Coexistence is where the cost of a merge sits. The mailbox transfers themselves are routine; keeping two estates usefully interoperable while people continue working is the engineering.

Splitting an estate after a disposal is the same project with the opposite sign. A subset of users, their mail, their files and often a subdomain leave for a new tenant, and the constraint is data ownership rather than identity collision: which files belong to the departing entity, who decides, and what retention obligations follow the data.

We treat the classification decision as yours, made with your counsel. We build the mechanism and evidence trail; we do not adjudicate what belongs to whom.