Tuesday, June 25, 2024
Home » Office 365 » How to Migrate Mailboxes Between Office 365 Tenants – Complete Guide

How to Migrate Mailboxes Between Office 365 Tenants – Complete Guide

Written By Mohit Jha
Mack John
Approved By Mack John  
Published On June 22nd, 2023
Reading Time 7 Minutes Reading

With evolving businesses, there comes a situation where they need to undergo mergers, acquisitions, or a change in business structure. All these operations lead to performing data migration from the old work environment to the new, in order to maintain productivity and preserve valuable data. 

However, it becomes a daunting task to migrate mailboxes between Office 365 tenants, but it becomes a necessary task if you are undergoing mergers and acquisitions. Hence,  in this article, we are providing a detailed, step-by-step guide on how to migrate mailboxes between Office 365 tenants.

Let’s have a quick glance at the user query first:

User Query: What are the ways, that can help me learn how to migrate mailboxes between Office 365 tenants? I haven’t yet found an easy-going technique for the migration process. It has been days since I have been trying to look for a solution that can help with a quick procedure since there are more than 500 users that I need to migrate. Please help!


As we know, a tenant is the domain account that is attached to the Office 365 Suite. The administrator of a tenant, having the benefit of using all the features offered in the subscription plan, also takes care of the migration part. Whenever there is a requirement for migrating user mailboxes, the administrator has to make all the preparations.

There are some prerequisites that are to be considered before executing the migration task. We will explain a simple approach that can help with an easy operation to transfer mailboxes. You shall also find the steps for this process in the section later. Let’s get started!

Prerequisites to Migrate Mailboxes Between Office 365 Tenants 

Check out the following steps:

Step 1. Assess the Migration Scope and Requirements:

Before migrating mailboxes between Office 365 tenants, it is important to evaluate the scope of the migration and determine the exact requirements. You have to specify the number of mailboxes that need to be migrated, their respective mailbox sizes, and any particular migration constraints. Then it is suggested to evaluate factors like the available network bandwidth, the migration timeline, and the need for coexistence during the entire migration process.

Step 2. Set Up the Target Office 365 Tenant:

You must now create a new Office 365 tenant to serve as the destination for the mailbox migration. Begin by creating the necessary user accounts, security groups, and mailbox databases in the destination tenant. Then, you must assign appropriate licenses to the users who will receive the migrated mailboxes.

Step 3. Prepare the Source Office 365 Tenant:

Now you need to make sure that the source Office 365 tenant is properly configured for the migration. Furthermore, you have to verify that all mailboxes are in a healthy state without any issues or errors. Then, you have to check and ensure that all the required administrative permissions are in place to migrate mailboxes from one tenant to another in Office 365.

Step 4. Establish a Migration Plan:

Prepare a comprehensive migration plan that includes a timeline, communication strategy, and any necessary contingencies. Determine which migration method to use, such as direct, staged, or hybrid, based on the specific requirements and constraints of your migration project.

Step 5. Configure Mail Flow and Coexistence:

If the migration process involves a hybrid configuration, establish a mail flow and coexistence between the source and target tenants. This will make sure uninterrupted email communication between users in both environments during the migration process.

Step 6. Migrate Mailboxes:

Once the preparations are complete, it’s time to start migrating the mailboxes. Depending on the chosen migration method, follow the appropriate steps:

Instant Solution to Migrate Mailboxes Between Office 365 Tenants

Here, we have this easy-to-use solution that beats the working of the manual procedure since it takes a lot of time, days even, and requires a lot of technical expertise. There may be users who have no knowledge in this arena and are finding it challenging to transfer the data. This solution is also recommended by experts for a trouble-free migration.

This is the Office 365 to Office 365 Migration using which you can easily migrate the entire mailbox or any item from the mailbox such as Emails, Contacts, Calendars, Tasks, Categories, and Documents. There are also options to export the archive folder from the accounts. Using this tool you can also migrate Office 365 mailbox to another account safely.

Let’s check out the steps for the migration.

Migrate Mailboxes from One Tenant to Another Office 365 Using the Tool

First, check out the pre-requisites for the software that includes the following:

  • Make sure the destination user(s) are already created in the destination admin account.
  • Creation of a project in MS Azure, application permission, and application ID are a must.

Once you have these, you can go through the steps listed below:

1. Launch and Run the software and click on the Activate button on the bottom left corner of the windows. Choose the Setup tab and select Office 365 as Source and Destination.

2. Mark the categories you want to export and then choose the Date-Filter option for each category if required. Enable the Use Group Mapping option.

3. Enter the credentials for Source Office 365 and Validate to learn how to migrate mailboxes between Office 365 tenants.

4. Input the Destination Office 365 credentials, hit Validate, and click on the Next button to move forward.

5. Select the Fetch Users option and hit Continue for the next step. Enter the Destination emails to start the migration process.


6. Set the Priorities as needed, click the Validate button, and hit Start Migration to start the operation.

The software will complete the task and show the status of the process and an export report can be generated if required. Also, users can choose to stop the process in between as per convenience by clicking on the Stop Migration button.

The Date-Filter provided by the tool to migrate mailboxes from one tenant to another Office 365 allows users to export data selectively from the mailboxes. You can set a date from and to for exporting data from the required time zone.

There is an option to Re-Run Migration after performing the transfer process and offers 3 modes:

  • Retry Failed Items: Option to export failed or skipped items from the previous export process.
  • Re-Run Full Migration: To run the entire migration procedure again, you can choose this feature.
  • Delta Migration: In case you receive new emails, the software can easily export the newly acquired data from the mailbox using this function.

Here, we have another method which is a lengthy process. We will be mentioning all the steps of preparation to give users a basic idea of what needs to be done.

Step 7. Verify and Test Mailbox Migration:

Verify the migrated mailboxes in the target tenant in detail after the migration process is finished. Test calendar synchronization, mailbox accessibility, and other crucial features. Verify the successful migration of all data, including emails, contacts, calendars, and settings.

Step 8. Update DNS Records and Decommission the Source Tenant:

Update DNS records to point to the new Office 365 environment. Redirect mail flow and make sure all client devices are configured to access the migrated mailboxes. Once the migration is considered successful, decommission the original Office 365 client in accordance with your organization’s policies and requirements.

Also Read: UPLOAD PST TO OFFICE 365 Using 4 Different Approaches

Putting Everything All Together  

In this write-up, we have discussed a step-by-step process to that will help you migrate mailboxes between Office 365 tenants. Follow the above-mentioned prerequisites and use the automated tool to ensure an error-free and safe migration without any data loss.