Case Studies Merger/Divestiture Office 365 Project for Manufacturing Firm

Merger/Divestiture Office 365 Project for Manufacturing Firm

Concurrency implemented a successful cross-tenant migration project for a global manufacturer undergoing branding changes due to corporate ownership transition. The project involved changing email addresses for approximately 1,300 users while maintaining the old addresses as secondary. Through meticulous planning and coordination with the client, Concurrency executed the migration from the old domain to the new domain, syncing data and avoiding user outages. Throughout the project, Concurrency collaborated closely with the client’s internal IT team, ensuring a smooth transition of all users to the new tenant and finalizing the migration successfully.


It used to be that when companies merged or separated—as in a divestiture or other change of corporate ownership—that user migrations were often highly time consuming but otherwise fairly straightforward.

That’s not the case with cloud offerings. While cloud solutions provide huge advantages for both users and administrators, cloud-related migrations are actually more thorny than on-premises migrations. Over time, more tools will no doubt emerge that make these processes easier. But for now, it’s important to include careful tenant-migration planning and execution while looking ahead toward any change of corporate control.

Concurrency implements a proven planning and execution methodology to ensure success in what can otherwise be a surprisingly messy and difficult process.


We recently completed a cross-tenant migration project for a global manufacturer. As part of branding changes that tied into a corporate ownership change, users’ email addresses needed to change—while keeping the old address as a secondary address.

This need for change applied to approximately 1,300 users across multiple locations who were already up and running in both email and OneDrive services on the Office 365 platform.

Our client requested our assistance in planning and executing a migration that would sync data from the old domain onto the new domain—all while coordinating with a breakaway from an existing on-premises environment.
To accomplish this objective, we planned intensively through workshops and discussions onsite with our client. We needed to determine the precisely correct order in which to take each step to avoid user outages and other potential stumbling blocks. Many of these steps involved custom-created scripts, which we first planned and then wrote.

Using a third-party migration tool—BitTitan MigrationWhiz—we began syncing user content behind the scenes as part of the new environment preparations. We configured a new mail routing to accommodate cross-environment mail-flow (and access in both tenants). We then piloted user migration, followed by batches of 50-100 users at a time for the main group. For overseas users, we pre-staged and then executed a “big-bang” migration rather than handling in batches.

Throughout the planning and execution, we worked in cooperation with our client’s internal IT team. That included the early planning phases (following which we built out PowerShell scripts), the actual execution of the migration and, later, support for wrap-up needs. Once all users were moved onto the new tenant, we severed the mail forwarding relationships. At that point, the new tenant truly stood alone—exactly the desired result.