How to Split Office 365 Data Between Two Microsoft 365 Tenants
Question details
A company needs to separate one cloud-based Office 365 tenant into two independent tenants, transferring domains, user accounts, emails, and OneDrive files.
- Product
- Microsoft 365
- Device & OS
- not provided
- Scenario
- Splitting a single Microsoft 365 tenant into two separate tenants for different business divisions without using any on-premises servers.
- Observed behavior
- The organization needs to move 14 users and 3 to 4 custom domains to a brand-new tenant, securely migrating Exchange Online and OneDrive data.
Ensure you have global administrator credentials for the source Microsoft 365 tenant and that you have already provisioned the destination tenant with enough active user licenses.
Perform a Cross-Tenant Mailbox and OneDrive Migration
Use Microsoft 365 cross-tenant migration capabilities to securely move user accounts, mailboxes, and OneDrive files to the new destination tenant.
Tenant-to-tenant migration involves several distinct phases: environment preparation, data migration, and domain cutover. Since this environment is entirely cloud-based, you do not need to configure Active Directory synchronization or Exchange Hybrid deployments.
Log into the new Microsoft 365 admin center and purchase the required licenses for the 14 users. Create the target user accounts temporarily using the default .onmicrosoft.com routing domain.
Navigate to the Exchange admin center to initiate a cross-tenant mailbox migration. You will need to prepare the target environment with MailUser objects and establish an organization relationship between the source and target tenants.
Use the Microsoft 365 cross-tenant OneDrive migration feature to transfer files. You must configure the required Azure App registrations, grant consent, and run the migration commands via the SharePoint Online Management Shell.
Once the background data syncs are complete, remove the required custom domains from the source tenant. After successful removal, immediately add and verify these domains in the destination Microsoft 365 admin center. Finally, update the target users' User Principal Names (UPNs) and primary email addresses to use the new domain.
Try WPS Office as a Cost-Effective Productivity Solution
While separating Microsoft 365 tenants requires backend administrative work, providing robust productivity software to your newly separated users doesn't have to be complicated or expensive. WPS Office is a highly compatible, lightweight, and completely free Office suite that serves as an excellent alternative to costly subscription plans.
- 1. Download WPS Office: Visit the official WPS Office website and download the correct installation package for your operating system.
- 2. Install the application suite: Run the setup file and follow the quick installation wizard to equip your device with Writer, Spreadsheet, and Presentation.
- 3. Open your migrated documents: Seamlessly open, edit, and save your newly migrated Microsoft Word, Excel, and PowerPoint files natively in WPS Office.
Frequently Asked Questions
How long does a Microsoft 365 domain cutover take?
Removing a domain from the source tenant can take anywhere from a few minutes to several hours, depending on the number of objects (users, groups, aliases) tied to it. Adding it to the destination tenant is usually immediate, though global DNS propagation for MX and Autodiscover records can take up to 24-48 hours.
Do users lose access to their emails during a cross-tenant migration?
Users typically maintain access to their source mailbox until the final cutover phase. During the actual MX record change and domain cutover, there may be a brief period of downtime where inbound emails queue at the sender's end before being correctly routed to the new destination mailbox.
Can I perform a tenant migration if I have an on-premises Active Directory?
Yes, but the process is significantly more complex. You would need to manage Entra ID (Azure AD) Connect synchronization, potentially decouple the on-premises AD accounts from the source tenant, and re-establish directory synchronization with the destination tenant.
What is the simplest way to migrate a small number of users like 14 accounts?
For smaller user counts, manual data transfer is a viable option. Administrators can have users export their mailboxes to Outlook PST files and manually download their OneDrive files, then import/upload them into the new accounts. However, automated scripts or third-party tools are still recommended to prevent human error.
