Office 365 Tenant to Tenant Migration or Cross Tenant Migration

Written By Adom James
Updated on March 6th, 2025

Summary: Planning a Microsoft 365 tenant-to-tenant migration? Whether you’re rebranding, merging with another company, divesting, or consolidating multiple tenants, this guide provides comprehensive solutions for a seamless cross-tenant migration. We’ll explore the reasons behind tenant migrations, outline the manual process, discuss its limitations, and introduce a professional Office 365 Migration Tool to streamline the process.

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A Microsoft 365 tenant, typically ending in ‘onmicrosoft.com,’ is a dedicated environment providing your organization with various Microsoft services under one or more public DNS domain names. Migrating from one tenant to another involves moving all your data, users, and configurations to a new environment. Let’s explore why organizations undertake this complex process.

Table of Contents

Why Need to Perform Microsoft 365 Tenant-to-Tenant Migration?

There are many reasons why businesses and individuals need to migrate their mailbox data from one Tenant account to another. Below we discuss a few general causes that lead users to export data without any trouble.

Company Mergers & Acquisitions – Combining IT infrastructures.
Divestiture or Spin-Offs – Separating business units into distinct tenants.
Domain Consolidation – Managing multiple tenants under one domain.
Rebranding & Domain Change – Switching to a new domain for branding purposes.
Security & Compliance – Enhancing security and meeting compliance regulations.

It is time to learn the methods to export Office 365 data from one tenant account to another.

Step-by-Step Guide to Office 365 Tenant to Tenant Migration

The complete manual procedure for migrating a Microsoft tenant account to another tenant account consists of multiple steps. Every step should be executed in the correct order for a successful migration. However, there are chances of data loss. Follow the below steps carefully.

Phase 1: Pre-Migration Planning

Assess Your Current Environment:

Audit existing mailboxes, OneDrive, Teams, and SharePoint data.
Verify licensing compatibility between source and target tenants.
Consider security and compliance factors (GDPR, HIPAA, ISO 27001)

Step 2: Verifying Domains

After performing the above procedure, the next step is to verify the target domain in Microsoft Office 365.
You need to add the source domain in the admin center of the destination O365 account.
Add TXT records in DNS.

Note: A single domain should not be used by multiple tenant accounts. It will fail the domain verification. Also, the process may take up to 72 hours to verify domains.

Step 3: Schedule Office 365 Migration

Identify the desired user mailboxes for migration and prepare a CSV file that will be required for mapping.
After that, check the lowest TTL value of the source Office 365 tenant account on MX Records.
Prevent automatic synchronization of any modification in the source account by disabling the directory sync for the source tenant Office 365 account from the admin center.

Step 4: Initiating the Migration

a). Restricts the Mail Flow to Source Domain

The next step for Microsoft 365 Tenant to Tenant Migration is to change the primary MX record to an unreachable value so that it blocks the inbound mail flow from the destination account to the source Office 365 account. You can identify the MX record value from the TTL value.

b). Prepare Source Domain

First, you must remove the primary domain from all the source tenant objects.
After that, set the initial email address as the default email address of Office 365.
From the source tenant, delete all Lync licenses using the Lync Admin Portal.
Again set the initial domain as the default domain for distribution lists, resources, and chat rooms.
Then, remove the destination Office 365 account from all source objects.

C). Prepare the Target Domain

After one hour of the previous step, you need to verify the source tenant in the target domain.

Configure the CNAME and if you use AD FS, also configure the new domain in the target tenant.
Set up licenses and other configurations for new user accounts in the destination domain.
Assign the source domain as the primary email address for new users.
Once the user mailbox is activated, direct the MX Records to new Office 365 email addresses.
At last, check the mail flow in and out from the destination domain.

Two Migration Scenarios:

When you have 500 user mailboxes or less, you can migrate emails, contacts, and calendars separately. Also, you can set restrictions for email migration based on dates and other parameters.
When you have more than 50 user mailboxes to migrate, the multi-pass method is the most reasonable approach to migrate contacts, calendars, and single-week data in multiple batches.

The above-explained Office 365 tenant-to-tenant migration step-by-step guide enables you to perform Microsoft tenant-to-tenant migration or cross-migration. However, it does not ensure complete data migration. Also, some of your mailbox data may get lost during the migration. Thus, you become unable to export complete data from one Office 365 tenant account to another tenant account. Now, you might be thinking if the manual approach is not reliable what else should we do? The answer is the professional Office 365 Migration Tool.

Automated Solution for Microsoft 365 Tenant-to-Tenant Migration

CloudMigration Office 365 Email Backup Tool is a professional solution to migrate data from your Office 365 account. With this utility, you can migrate one Office 365 tenant account to another tenant account. Along with that, this application allows you to exclude unnecessary items and migrate only accurate mailbox data. The Office 365 Backup Tool is an easy-to-use and reliable solution for exporting your Office 365 account. You can use the application on any version of your Windows OS.

Steps for Office 365 Cross Tenant-to-Tenant Migration

Download and launch the Office 365 Email Migration Tool.
Provide the desired login credentials and log in to your Office 365 account.
Check the available mailboxes of the Office 365 account. Hit Next.
After that, check the mailbox preview and choose desired items. Press Next.
Enter the login credentials of the destination Office 365 tenant account and click Sign In.
After successfully signing in, choose the migration parameters and click Next.
Again press the Next button and hit Convert to initiate the Office 365 tenant migration.

Conclusion

Migrating Microsoft 365 tenants is a complex but necessary process for businesses undergoing mergers, domain changes, or restructures. While manual migration is possible, using an automated migration tool ensures seamless, secure, and error-free cross-tenant migration.

Frequently Asked Questions

What is an Office 365 tenant account?

An Office 365 tenant account has an ending ‘onmicrosoft.com’. It is a set of subscription services allocated to each user of that particular domain.

How to migrate a tenant to another tenant in Office 365?

You can migrate your Office 365 tenant account to another tenant account by using the manual DIY solution and professional tool. The first approach is suitable when you have the technical expertise to execute the procedure because the steps are quite complicated. However, the professional offers advanced features and is suitable for all users.

About The Author:

Adom James

I’m Adom james, a skilled content strategist with a focus on technical writing. With in-depth knowledge in Email Backup, Data Recovery, and Email Migration, I specialize in providing expert solutions and addressing technical challenges for both individuals and businesses, especially in the areas of Cloud Backup and seamless email transitions.