/ Case Studies / Corporate Divestiture: Cross-Tenant Domain Migration Case Studies Corporate Divestiture: Cross-Tenant Domain MigrationOverviewOur client, an industrial company serving the energy sector, was in the process of separating from its prior parent company. The organization needed assistance with a complex set of needs related to migrating user accounts and mailboxes from the prior Office 365 tenant to the new one.While cloud solutions offer significant advantages over on-premises platforms, sometimes their migrations are actually more complex. It’s important to include careful tenant migration planning and execution while looking ahead toward any change of corporate control.In this cross-tenant migration project, we implemented a proven planning and execution methodology to ensure success.SolutionOur client needed to accomplish this migration project quickly due to constraints relating to the corporate divestiture schedule. Concurrency’s project team, which included an architect and an two engineers, worked quickly to determine the best way to handle our client’s complex web of on-premises user accounts in multiple Active Directory forests—and multiple domains within those forests. We built a custom runbook to govern the handling of user accounts of each type. In this way, we ensured that the proper migration procedures would be applied to all users.Having created the runbook, we then used BitTitan MigrationWiz to migrate 2,900 mailboxes, OneDrive, and email archive files to a new Office 365 tenant over a five-week period.Throughout this process, we worked with our client’s admins and helpdesk employees to optimize processes for onboarding and offboarding. We also helped our client improve its license management—and save costs—by better managing terminated and short-term employee accounts. In the process of migration, we converted more than 800 distribution lists into Office 365 Groups.