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How to Migrate Mailboxes from One Tenant to Another in Microsoft 365? Step-By-Step

Published By Ashwani Tiwari
Tej Pratap Shukla
Approved By Tej Pratap Shukla
Published On March 27th, 2024
Reading Time 8 Minutes Reading

Summary: This comprehensive article outlines all of the necessary steps for a successful data transfer in Office 365. To migrate mailboxes from one tenant to another without errors or data loss, read and follow each step described below.

There are various conditions, where the need for data migration arises within business organizations. It might be a merger, acquisition, rebranding, etc. however, there is no manual solution that can completely move Office 365 tenant to another tenant. Microsoft still suggests third-party migration software, when it comes to migrating Office 365 from one tenant to another. Therefore, in the coming section, we are going to discuss the initial steps, premigration preparation, domain verification, and other important steps and checklists in detail, to avoid any errors to migrate mailboxes from One Tenant to Another.

It’s Always a Good Approach to Plan Two weeks Before You Migrate

Migrating all the organization’s data is a massive activity to perform. We should ensure all the best practices and approaches for the same.

It’s always the best idea to prepare a comprehensive plan before two weeks to avoid the last-minute rush. Let’s discuss a few important checklists for the same.

Initial Steps That You Need to Take:

In the very first step before starting to migrate mailboxes from one tenant to another, you need to create the source users, groups, and all other objects in the destination tenant manually. You can use the PowerShell scripts or through Active Directory Domain Services (AD DS) consolidation to merge into the destination tenant.

Client Considerations 

If any of these tenants, using Outlook 2010 or above, then you must remove the Outlook user profile and need to create it again.

If you are working with Outlook 2007 or 2010, then after restarting the client, auto-discover will configure the client and OST is also built.

Also Read: How to Archive Office 365 Email Account?

Ensure Tenant Preparation and Licensing

As we are migrating mailboxes from one tenant to another, then there might be scenarios, where you need to increase user licenses in the destination tenant.

Also, ensure that destination user accounts have enough storage space and respective licenses. You will require an admin account for both source and destination while performing the migration in Microsoft 365.

Create Users, Distribution Groups, and Other Objects in the Target Tenant

You need to create the source users, groups, and all other objects in the destination tenant manually if you are using the Azure AD Connect tool. You can use the PowerShell scripts or through Active Directory Domain Services (AD DS) consolidation to merge into the destination tenant.

This operation can be done via various AD DS tools. Moreover, this task can take extra time and planning depending on the number of objects and users that need to be moved. Therefore, it should be completed before the migration project.

Must Read: How to Restore Office 365 Deleted Mailbox efficiently?

Proper End-user Communications

Now, you should make a communication plan and start informing users of the upcoming migration and service changes.

Important Preparation & Pre-migration Activities: Three Days Before You Move Office 365 Tenant to Another Tenant

Now follow these important steps before the data transfer operation:

Domain Preparation

Here, you need to begin the domain verification process on the destination tenant for the source email domain.

Then, in the destination tenant go to Microsoft 365 admin center, add the source domain, and create TXT records for the same, in Domain Name Systems (DNS) for respective verification. This process can take plenty of time and up to 72 hours to reflect.

Migration Scheduling

In this step, you need to create a list of users’ mailboxes that you want to transfer from source to destination.

For this step, you can create a CSV file that later will be used by the migration tool in order to create a mapping.

Modification of Time to Live (TTL) Test

Now, you have to schedule the TTL test. In order to accomplish this task, you need to change the TTL value in the DNS setting while browsing to MX record for the primary email domain you wish to transfer to a small number (i.e. 5 minutes).

Make sure it needs to be changed 4 hours before your migration begins. You can verify these settings and changes in MX lookup.

Disable Directory Sync in Source Tenant

This is the last and most important step before migrating Office 365 from one tenant to another. Go to the source tenant O365 admin center, here, you need to disable directory sync.

It can take up to 24 hours to reflect the changes and hence, need to be done before the migration. Once, you have done the same, from now onwards any changes in the source Office 365 tenant AD DS will no longer sync to the Office 365 organization. Now we are all set to move toward the migration process.

Reasons to Switch to Automated Solution Over Manual Method to Migrate Mailboxes from One Tenant to Another

The manual method of migrating mailboxes from one tenant to another has several limitations, including:

  • Time-consuming: The manual method of migrating mailboxes requires a significant amount of time and effort, especially if the number of mailboxes is large.
  • Risk of data loss: There is a risk of data loss during manual migration due to human error, such as accidentally deleting or overwriting data.
  • Limited scalability: Manual migration methods are typically not scalable, making it challenging to migrate a large number of mailboxes quickly and efficiently.
  • Inadequate security: The manual method of migration can be vulnerable to security threats, such as data breaches or unauthorized access, as it lacks the necessary security measures and controls to protect sensitive data.
  • Lack of automation: The manual method does not offer the automation and scripting capabilities that are essential for efficient and streamlined migrations.
  • Technical challenges: The manual method requires a high degree of technical expertise, making it challenging for non-technical users to complete the migration process.

Overall, the manual method of migrating mailboxes from one tenant to another is time-consuming, prone to errors, and lacks the necessary security, scalability, and automation features needed for efficient and effective migrations.

Top-Rated Software on How to Move Office 365 Tenant to Another Tenant

Now after ensuring all the above checklists and steps, it’s time to perform the migration task in the most secure way. In order to do that, we have to use the Most Reliable Office 365 to Office 365 Migration Software for this operation. We suggest the above-mentioned tool, this is a brilliant solution, specially made for Office 365 migration operations.

It ensures maximum data security and integrity while offering a smooth data transfer experience to its users. It can easily migrate emails, contacts, calendars, tasks, and documents as well. Here are the software steps for the same.

Download Now Purchase Now

Follow Software Steps to Migrate Mailboxes from One Tenant to Another Step by Step

Step 1. Run the software and select Office 365 as the source and destination. Check the email, contact, calendar, and document checkbox in the migration process.

Source and Destination

Step 2. The tool provides a Date-based filter, and it migrates document permission, uses group mapping, and also document permission. Enable the required mailbox categories and click on Next.

select workload items

Step 3. Now, log in to the Office 365 source tenant with Admin ID and Application ID. Then, validate permissions and click on Next.

Source Account credentials

Step 4. Log in to the Office 365 destination with Admin ID and Application ID, and click on the validate permissions. Click Next to migrate mailboxes from one tenant to another.

Step 5. Here are three options – Fetch User, Import users, and Download Template.

Fetch Users

Step 6. Now, we have to create a mapping between source and destination users. Click on the Download template. In this CSV file, you have to mention the source domain user ID and destination user ID. Then, upload it to the software..

Step 7. After that, validate the required permissions by clicking the validate button.

Step 8. Now, click on the Start Migration button.

Start Migration

Final Verdict

We have successfully described each step and checklist for a safe and successful data transfer in O365. Hence, users are advised to follow the same to avoid any error or complications, that may further create data loss.

Also, it is suggested to use the above-mentioned software to migrate mailboxes from one tenant to another, as it ensures maximum data protection in minimum time, and does not require any PowerShell scripts of prior technicalities.

Frequently Asked Questions

Q1. Do we need to create users, and groups in the destination tenant?

Ans – Yes, before migrating the mailboxes to the destination tenant, we need to create users and distribution groups.

Q2. What are the steps that should be taken before migrating mailboxes from one Office 365 tenant to another?

Ans – Below are the pre-migration steps:-

  1. Tenant Preparation and Licensing
  2. Create required objects.
  3. Verification of Domain.
  4. Scheduling of Migration.
  5. Update MX and TXT records

Q3. How to migrate mailboxes from one Tenant to another easily?

Ans – Use the above-mentioned automated tool for the successful migration of mailboxes with the below steps:-

  • Step 1. Download and set Source and Destination.
  • Step 2. Choose items and complete the required credentials.
  • Step 3. Load users and Map users.
  • Step 4. Finally, start migration.

Q4. What are the benefits of using an automated tool for transferring mailboxes to another tenant?

Ans – By using the automated tool, a lot of time is saved, chances of human errors are reduced, no need for technical knowledge, and so on.


By Ashwani Tiwari

I am an Expert Technical Analyst, specialized in assisting users with complex technological challenges. Through my blogs and articles, I offer expert guidance to help tackle these technical issues effectively. My true passion lies in providing valuable insights and simplifying complicated technicalities, enhancing user understanding and confidence.