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How to Merge Office 365 Tenants? A Simple Step By Step Guide

Published By Mohit Jha
Anuraag Singh
Approved By Anuraag Singh
Published On October 27th, 2023

Office 365 has emerged as the most prominent business solution. In today’s space, Office 365 offers unmatched productivity with a host of collaborative solutions. These solutions are being used across industries which raises the query – How to merge Office 365 tenants? Merging two Office 365 tenants simply means migrating the user accounts from one Office 365 tenant to another. 

5 Simple Steps to Combine Office 365 Tenants Quickly

  • Step 1. Download, install and run the software on your computer.
  • Step 2. Choose Office 365 as source and destination platforms.
  • Step 3. Select required mailbox categories and apply date filter.
  • Step 4. Login with Office 365 admin and validate permissions.
  • Step 5. Create mapping, validate permissions and click on start.

This might seem like an easy enough task but in reality, this process is extremely intricate and requires a lot of preparation. The organization would face loss of crucial data if this process is not performed with extreme care. Microsoft is not offering any straightforward solution for this. But, here we will discuss a secure and effective method to answer – How to merge Office 365 tenants?

Possible Reasons for Merging Tenants in Office 365

The requirement to combine Office 365 tenants might arise in several scenarios. An organization undergoing massive changes would definitely want to know how to merge Office 365 tenants. Some situations that would lead to merging the tenants in Office 365 are:

  • In case the company is merging with another company to expand its market share in its industry.
  • If an organization acquires another organization, the user accounts would be moved to another tenant for better collaboration between employees.
  • Merging two Office 365 tenants is the only option when there is a need to move the user accounts from the child company tenant to the parent company tenant.

Prerequisites to Combine Office 365 Tenants

Before starting with this process, there are some that the user should complete ensuring the smooth transfer of all the data. If the user fails to complete these tasks, the consequences would be dire. There might even be some loss of data. Let’s look at the prerequisites.

  • The person performing the merger should have admin access to both tenants.
  • The user should assign the appropriate licenses to the destination accounts so that the users don’t face any problems in accessing the data stored in their accounts post-merger.
  • Create user accounts on the source tenants and also create a CSV file to map the source and destination user accounts.
  • Set the TTL(Time To Live) value as low as possible to ensure the migration of the latest data when the user has to combine Office 365 tenants.
  • Train the end users for using the Office 365 application post-migration.
  • The MX record value of the source tenant should be changed to stop the flow of emails to the account.
  • It is necessary to communicate with the end users about the migration process. The users might end up confused and clueless after the merger completes if they are not properly communicated with.

Must Read: OneDrive Migration Best Practices – The Step By Step Ultimate Guide

How to Merge Office 365 Tenants? Recommended Way

There are varying requirements of organizations when it comes to merging tenants in Office 365. There is one method that satisfies every use case and gives the best result. The software is SysTools Office 365 Migration Tool. It is used by leading IT professionals and has garnered a good reputation among industry professionals. The tool offers the user so many functionalities that the process becomes of merging tenants in Office 365 becomes extremely easy. Here, we will discuss how to merge Office 365 tenants.

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Let’s look at some features of the software:

  • User has the option to customize the workload as per their requirement. This means the user can choose from Emails, Contacts, Calendars, Tasks, and Documents.
  • The user can further customize the workload using the Date Filters. This lets the user selectively migrate the data.
  • The software supports the migration of Shared mailboxes as well as In-Place Archive mailboxes.
  • Using the Delta Migration facility, the user can restart the migration process to migrate the data that arrived during the previous migration procedure.
  • There are priority settings to pre-define the sequence in which the user accounts will be migrated.
  • The tool can migrate the data from different Office 365 applications including Microsoft Teams.
  • The tool provides an additional layer of security by requiring Admin credentials to migrate multiple user accounts.

Follow Steps to Combine Office 365 Tenants Using Automated Software

Step 1. Install and activate the Office 365 migration tool.

Step 2. Select the source and destination platform as Office 365 from the Setup tab.

Step 3. Select the workload under the workload section. Here, the user can also use the date filter, if required.

Step 4. Now, provide the necessary credentials for the source account and press Validate to combine Office 365 tenants.

Step 5. Repeat the previous step [p for the Destination tab as well.

Step 6. Now, map the source and destination user accounts by choosing the suitable option from the screen and press Validate to verify the permissions required.


Step 7. Press Start Migration to start merging the tenants of Office 365.

These steps are extremely easy-to-follow. The software serves the user with a simple and intuitive user interface. This is the tool user should use when they want to know how to merge Office 365 tenants. Using this tool, even a technologically illiterate person can perform this highly technical task.

Also Read: How to Use PowerShell to Perform Office 365 Staged Migration – Complete Guide

Free Trial Version 

This software comes with a free trial version using which you can easily merge two Office 365 user accounts for free. In this way, you can verify the working and performance of this utility at no additional cost. Try the demo version now!


How to merge Office 365 tenants? This is easily one of the most complicated procedures an IT professional would come across in their career. The lack of a solution from Microsoft makes this task more complex. This is one of the reasons why this article presents a dedicated solution.  This tool is suitable for professionals as well as people with less experience with technology. Also, the features of the tool are unmatchable which further assists the user in combining Office 365 tenants.