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Office 365 Tenant To Tenant Migration: Detailed Guide

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Published By Mohit Kumar Jha
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Published On June 3rd, 2025
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Migrating from one tenant to another in Microsoft 365 is a major task that requires extensive planning and preparation. However, with a good plan, admins can easily perform this complex task with flying colors. In this article, I will give you some insights and also give you some very useful tips that will make the process smooth.

Office 365 tenant to tenant migration is a process that allows users to move data from one Office 365 tenant to another. This process proves to be useful when organizations undergo mergers, acquisitions, and divestitures. With comprehensive planning, this complex migration can be done with no hassle while ensuring the productivity of the entire team.

Before we begin, we need to discuss what you should be considering when you want to perform an Office 365 tenant-to-tenant migration.

What You Should Consider in an Office 365 Tenant to Tenant Migration?

There can be many different reasons why a user might want to perform a migration process. Many different approaches can be taken by the users to perform the migration.

But, before that, let us discuss the scenarios due to which a user may want to migrate their documents and other important data:

  1. Mergers: When two organizations combine to become one single entity, they would also have to merge all of their data.
  2. Acquisitions: When an organization absorbs another business completely, it needs to migrate its data to the organization.
  3. Reorganisation of businesses: When a business reorganises, such as moving its locations, or wants to shift from one tenant to the other. In this case, migration of data is a must.
  4. Divestment of a business: When a business is purchased by a larger organisation or restructured, it needs to perform Office 365 to Office 365 migration.

What are the Types of Office 365 Tenant to Tenant Migration?

Two types of tenant-to-tenant migration suit the majority of cases:

  • Tenant-to-tenant migration is done in phases –
    • The process of migrating data is done gradually.
    • Suitable for any scale of Office 365 tenant-to-tenant migration.
    • The users assume a new domain in the destination tenant.
    • It has a longer runtime but has a lower risk associated with it.
  • Tenant-to-tenant migration that is done in one go –
    • The migration of data is completed in a single event.
    • It has a shorter timeline but has a higher risk.
    • It is suitable for migrations that have users below 15,000 or a size of 7 TB.

Which Type of Tenant to Tenant Migration Should You Choose?

While migrating, you have the option of moving your important data and other documents from the source to a single destination tenant or into several tenants. In this section, we will discuss the benefits as well as the limitations of the types of migration:

  • Single tenant migration –

This is the most common way that organisations and businesses use to migrate their data. It is also the best option for most businesses as it is a simple process. It allows users to collaborate seamlessly through all the applications offered by Microsoft. Single-tenant migration allows organisations to simply secure the destination tenant.

  • Multiple tenant migration –

This type of migration is suitable for businesses that have several departments, are located at different locations, and have a global user base. This means that the organisation would have to deal with several license providers.

The main difference is that this process becomes a little more complicated. This is because users from the source tenant would have to be the guests of the other tenant. Securing these guest permissions is much harder.

Potential Risks With Migration

Planning the migration process is a must since there are several risks involved in this process. Here, we discuss the main risks that you should consider:

  1. Discontinuation of business – You should plan the migration in detail since the migration process can stop the daily activities of the business.
  2. Loss of productivity – Users should be able to access files, contacts, emails, and other documents in order to be productive. So you should plan accordingly to maintain the productivity of the business.
  3. Clutter – If you don’t plan the destination tenant, there is a risk that the environment will be very cluttered. This would make it much harder for users to find what they need in order to be productive.

Best Practices for Office 365 Tenant to Tenant Migration

The migration process can be a complex task, and inexperienced users can easily get confused. In this section, we provide the best practices that users should keep in mind before starting the migration process. Here are the best practices for Office 365 tenant-to-tenant migration:

Understand the migration process

You should have well well-thought-out plan that is crucial for successfully migrating to the source tenant. There are several things that you need to consider before making the move. No two businesses can have the same requirements, so creating a plan that is tailored to your needs is very important. Here are a few points that you should keep in mind:

  1. Assessing the risks: The risks include data loss, difficulty in collaborating with other employees, downtime, and added costs.
  2. Listing the opportunities: You can make a list of all the opportunities the migration process will present, such as modernising the structure, lowering the costs of storage, as well as licensing of the plans.
  3. Future-proofing your tenant: You can limit the number of instabilities that can occur in the future due to older tenants. By migrating to a newer tenant, you can make sure that your organisation is ready for the changes in technology and the changes that will happen in business over the years.
  4. Setting up governance policies: You can set up guardrails to ensure that all the users in the organisation comply with them.

Fixing the Issues at Source Tenant

Users should address security problems in the source tenant before starting the migration process, instead of bringing these problems over to the destination tenant. Since Microsoft 365 security focuses more on external sharing, this is a critical aspect since these problems cannot be fixed after the migration process is complete.

Preparing the Destination Tenant

The migration process is the best opportunity for users to restructure and organise the source tenant so that all the data can easily be found by the users. Doing this will also improve the collaboration between teams and improve productivity.

What are the Various Stages of Office 365 Tenant to Tenant Migration?

The various stages are:

Step 1: Planning the Migration

Planning is a very important part of the migration process. You should make a clear roadmap and identify the objectives. This way, you can carry out a hassle-free migration process. It is advised that users plan for the migration process at least two weeks in advance. Below are the points that you should consider while creating a plan:

  • Preparing the tenant – 
    • All the mailboxes need to be accommodated in the destination mailbox. So, it is a good idea to increase the destination licenses.
    • You can create accounts for both the destination and the source in advance to perform the migration process.
  • Creation of resources at the destination – 
    • If there are any rooms, resources, users, or groups that are managed in the Office 365 admin centre of the source, then you can create these in the destination. These can also be created manually through Windows PowerShell commands.
  • Communication with the end user – 
    • You should communicate clearly with the staff about the migration process and make it known.
    • Make sure that all the users know how they can connect Outlook on the web using their new information.

Step 2: Preparing for the migration

It is important to prepare a comprehensive Office 365 migration checklist. Here are the following points that should be included:

  • Preparing the domain
    • You can start the verification process on the source Office 365 tenant.
    • You should add the source domain and make TXT records in the Domain Name System to verify the destination Office 365 admin centre. This process can take up to 72 hours.
  • Scheduling the migration process
    • You should prepare a list of Office 365 user mailboxes.
    • Make a .csv file to match the source mailbox with the destination.
  • Scheduling a TTL Test
    • Change the TTL value on the MX record in DNS for the primary email. Set it to the lowest value.
    • Validate the changes made through MX Lookup.
  • Disable the Directory Sync
    • In the admin centre, disable the directory sync. This process can take 24 hours or more, so the directory sync feature must be disabled before the migration process is started.

Step 3: Initiation of the Migration Process

  • Stop the incoming mails
    • Change the primary MX record so that it is unreachable. This will queue the new emails and try to redeliver them after 24 hours have passed.
    • Remove Lync licenses from the source tenant using the admin portal.
    • Reset the default source email addresses in Office 365.
  • Preparation of the destination tenant
    • Configure the auto-discover CNAME.
    • Set up the new domain in the destination ADFS if you are using ADFS.
    • Set the source email domain as the primary address using PowerShell.
    • You can also configure passwords on all mailboxes in the destination tenant.
    • Verify that the mails are reaching the destination tenant.
    • Make the mail flow rules in the target tenant.
  • Start the Office 365 tenant to tenant migration
    • After all of this planning, you can initiate the migration process. Take the help of the automated tool so that you can smoothly execute the migration process. Using an automated migration tool can allow you to migrate unlimited emails and also reduce the risks involved.

Step 4: Post Migration

After the migration process has completed, you should perform a clean-up. You should make sure that you clear the Outlook auto-complete list. You should also ensure that all the source mailbox data, as well as the important emails, are migrated to the destination tenant. Arrange training sessions so that the staff member can learn about the new environment that you migrated to.

Which Services Can be Migrated?

In the table given below, we will tell you about the services that can be migrated currently:

Services Possible to Migrate Note
Office 365 Applications Yes
Exchange Mailboxes Yes Migration can be done through Microsoft consulting services (MCS) or any other automated migration tool.
Exchange Public Folder Yes Migration can be done through MCS or any other automated migration tool.
SharePoint Sites Yes Migration can be done through MCS or any other automated migration tool.
OneDrive Yes Migration can be done through MCS or any other automated migration tool.
Groups in Office 365 Yes Migration can be done through MCS or any other automated migration tool.
Teams Partially Migration can be done through an automated tool and scripts to recreate the environment.
Yammer Partially There are limited scenarios that are supported.
Azure Information Protection Partially There are limited scenarios that are supported.
PowerBI No
PowerApps No
Intune Yes Users would have to unenroll their devices and re-enroll them in the destination tenant.
Windows 10 subscription License Yes Users need to join the Azure AD domain of the destination tenant and sign in with their new destination tenant account.

As you can see in this table, you would have to migrate all the services separately. This would be a very time-consuming process. It could prove to be extremely complex, too, which could lead to errors and also could lead to data loss. In the next section, we are going to discuss the solution to this problem.

Ensuring Successful Migration Every Single Time

So, how do you ensure that your Office 365 tenant-to-tenant migration is successful? The manual methods to migrate are very complex, and you would have to perform the migration process for every service separately. This will take up a lot of time, and the chances of an error will increase. You can prevent this by using an automated tool that migrates all of your data in a very short time.

One of the best tools in the market that does all the heavy lifting for you is the SysTools Office 365 to Office 365 Migration Software.

This tool will help you migrate all your files and other documents that are important to you with total security. It also ensures that it can move the files quickly so that your productivity is not affected.

 Download Now  Purchase Now

Here are the features of this tool:
  1. Emails, documents, contacts, calendars, and much more can be migrated using this tool.
  2. This tool migrates Shared mailbox to Office 365.
  3. It can migrate data from one Teams to another seamlessly.
  4. An option to filter data by dates for the migration process can also be done.
  5. You can import a CSV file that can be added to the source and destination accounts.
  6. This tool helps you migrate entire or selective mailboxes by using the admin account.
  7. A feature of delta migration is also available that can migrate newly arrived items.
Here are the steps you can use to migrate your data using this tool:

Step 1. Select the source as well as the destination as Office 365.

Select source and destination

Step 2. Select the category that you want to migrate under the workload section.

Workload Selection

Step 3. You can filter content based on dates by using the date filter option of date-filter.

Date Filter

Step 4. After you have selected them, click on Next. Enter the admin and application ID of the source tenant.

Office 365 source details

Step 5. Click on Validate and then Next.Enter the admin and application ID of the destination tenant.

Destination Details

Step 6. Click on Validate and then select Next.Now you can fetch users and click on continue.

Fetch Users

Step 7. After the source Office 365 accounts have been fetched, the source mailboxes can be seen.

Users Fetched

Step 8. Click on the start migration button.

Start Migration

Conclusion

In this article, I have discussed the crucial aspects of the Office 365 tenant-to-tenant migration. When it is done manually, it can be very time-consuming, complex, and prone to errors. Therefore, I have also discussed the best practices that you should follow before starting the migration process.

Alternatively, I have also mentioned an automated software that can guarantee that every file and document that you own will get migrated. It saves a lot of time and effort for admins and keeps the security of the files throughout the entire process.