How to Merge Office 365 Tenants? Complete Tutorial

Recently we acquired a company to expand our businesses. But when it comes to merging their Microsoft 365 tenant with ours, I don’t know how to do it. I want a way where I can easily move my mailboxes, OneDrive, Teams and everything without disrupting the users. So, is there a solution where I can combine the two Office 365 tenants without data loss.

If you also want to do the same, then we are here to provide you methods to merge Office 365 tenants. So, without wasting any time we start the article.

Know the Structure of Office 365 Tenant

Before combining two or more Microsoft 365 tenants together. We have to first understand the structure of the tenant. Office 365 tenant is a Microsoft assigned account. When you first subscribe to Microsoft 365, you will be given a unique account known as tenant which contains all the users, services and data under one domain or multiple domains. The Office 365 tenant contains several components like Azure Active Directory, Microsoft 365 services, domains, licensing, etc.

Although it is not possible to directly merge Office 365 tenants. Because there are no built-in features to combine the tenants. But, you can do tenant to tenant migration to combine multiple tenants.

Pre-Merger Planning

It is important to first plan your merging with your tenants. In this you have to make sure certain things, which we have mentioned below.

• List all users, mailboxes, shared mailboxes and groups.
• Audit OneDrive, SharePoint, Teams, Planner and other services.
• Find out your data, custom configurations, and third-app dependencies.
• Search which domains are used in the tenant and find out which one will be retained.
• Review the current licenses and match them appropriate with the target tenants.
• Save your data to a secure place before combining your tenants.
• Communicate with every user and set the time period for the process.

Once you fulfill the checklist we know start the migration process.

Manual Merge Office 365 Tenants

Using Microsoft’s admin portal and the PowerShell scripts you can manually migrate your data. It is suitable for small organizations so let’s see how you can do it.

1. First, we create new users in the destination tenant. In the Microsoft 365 admin center, click on the Users button.
2. Select the Active Users and Add a user. Once you create a new user, assign the license.
3. To merge your two tenants we have to remove the domain from the source tenant.
4. Then, unassign the domain from all the users, groups, and aliases.
5. Set your UPNs to temporary default domain and delete DNS records.
6. Now, in the target tenant, go to the Admin Center. Click on the Settings and then Domains button.
7. Select the Add domain button. Enter the domain name that you removed.
8. Verify it with a TXT record in your domain registrar’s DNS settings.
9. After that, update your email address and UPNs into a new domain.
10. Configure your aliases and group email addresses.
11. Lastly, add the MX record to your target tenant.

So, this is the way to manually combine your tenants. If you are having problems following the above steps, you can go through this article for a detailed method.

Combine Two Office 365 Tenants with Hybrid Method

In the hybrid method, you run two Office 365 tenants in parallel for a fixed period of time. This method is used in merging, acquisition and large company migration. It is a risky method so carefully follow them.

1. Sign in to the Microsoft Entra Admin Center of the target tenant.
2. On the left hand side, click on External Identities, then Cross tenant access settings.
3. Click on the Default settings and enable access to apps and resources under the inbound access.
4. In the Outbound access, enable the access resources in the source tenant.
5. Go to the Organizational settings and click on Add organization.
6. Enter your source tenant’s domain and press the Add button.
7. Now, configure Inbound settings and outbound settings.
8. After confirming the account, save the changes.

Both the above methods are free and manual, but you may have issues following the methods. Therefore, we have a professional tool that can help you merge your accounts.

Steps to Merge Office 365 Tenants

1. Download and install the software.
   
2. Provide Microsoft 365 email address, password and login to the software as admin.
   
3. The software fetches your data in the software and you can preview them by clicking on them.
   
4. Now, select the Office 365 option from the saving options.
   
5. Provide the appropriate email address and click on Backup.
   

To Conclude

In this article, we have learned how you can merge Office 365 tenants. There is no direct way to do that. But, if you use the above methods, then you can get all your data in one account. Properly follow the methods and you can easily get your data.