Microsoft Office 365 Tenant to Tenant Migration – Step By Step Guide for Administrators

This writе-up outlinеs a detailed overview of the essential aspects of Office 365 tenant-to-tenant migration. Whether you’re undergoing a merger, acquisition, or rebranding, we will walk you through the key steps and considerations for the entire process. It will ensure a smooth and efficient transition for a successful cross-tenant migration in Microsoft 365.

Due to the popularity of Microsoft 365 in the market, most businesses globally have been using it for a long time. Moreover, there are various reasons why Office 365 is better than Google Apps. As per the natural business cycle, companies often acquire or merge with other companies or divide business units set up on their own. Apart from mergers and acquisitions or rebranding, if they want to transfer Office 365 subscription to a new computer all these situations create an urgent need for migration to M365. Hence, organizations often discover themselves in need of performing Microsoft Office 365 tenant-to-tenant migration. 

However, it can be a challenging task as it requires careful preparation, planning, and execution. Microsoft 365 is a widely used business productivity suite that delivers a variety of software for daily work collaboration and business communication. Hence, while migrating from one tenant to another in Office 365, it is a must to ensure minimal disruption to business operations and overall data integrity.  According to a recent study around 50-70% of migration projects face delays or fail to meet their initial goals due to inadequate pre-migration planning.

We will start with a thorough analysis of the current tenant environment, and the reasons for the migration. Then we will detail the key procedures involved in tenant-to-tenant migration to Office 365 throughout this article. Determining the scope of the migration and spotting any obstacles requires a thorough understanding of the current configuration, user accounts, data, and any customizations or integrations.

What are the Major Reasons Behind Cross Tenant Migration in Office 365? 

There are several reasons why an organization may need to perform this operation in Office 365. Some of the most common reasons are mentioned below:

• Mergers and Acquisitions (MA) Activity – While merging two or more companies, or one company acquires another, then, it becomes crucial to combine Office 365 tenants to have a single, and unified environment for better management.
• Rebranding – Another reason could be the rebranding process, as it requires changing the company’s name or domain. Making it compulsory, to move its data to a new tenant with a different name or domain.
• Consolidation – In situations, where companies have multiple Office 365 tenants, managing it could be a cumbersome task. Hence, it requires performing O365 tenant-to-tenant migration to simplify management and reduce costs.
• Compliance and Governance – Organizations might need to migrate their data to another tenant in O365 to comply with new regulations or meet new governance requirements. Hence, it can also be a reason for this operation.
• Scalability – When businesses grow, they require more resources and scalability in every aspect including Office 365. Hence, to upgrade their subscription, they have to migrate their data to an upgraded subscription plan.
• Cost Savings – It can also be a reason, that an organization may need to move its data to a new tenant just to reduce the costs associated with licensing, support, and other related services.

Furthermore, it is essential to note that manually performing Microsoft 365 tenant-to-tenant migration has its challenges and potential risks. It is recommended to plan, test, and execute the migration process carefully and with the help of professional migration tools/service providers. Hence, in the coming sections, we have covered all aspects of this operation for different business scenarios.

Different Business Scenario & Architecture Approaches

Let’s discuss the different possible business scenarios, architecture scenarios,s and the best possible architecture approach for tenant-to-tenant migrations in Microsoft 365. Let’s take the example of Contoso being the source tenant and Fabrikam being the target (destination) tenant. 

Business scenario	Architecture scenario	Architecture approach
If you sold a business unit and brand identity without rebranding Contoso users will continue to be known as [email protected]. Even after being acquired by the respective organization.	Tenant-to-tenant Migration Identities will move to a target (destination) tenant and will keep the existing domain as part of the migration.	Single-event Migration Migration typically occurs in a single event with all data, which entails higher risk but shorter timelines. Limit single-event migrations to no more than 15,000 users or 7 TB of site content to avoid complications. It might be a limiting factor to scale a few aspects such as data volumes, network bandwidth, and helpdesk capacity. Use a temporary domain for phased migration if a single event isn’t feasible.
Sold a business unit and the business unit will adopt the target company’s branding Contoso users will be known as [email protected]	Tenant-to-tenant migration with rebranding Identities will shift to a new target tenant and undergo a brand identity change as part of the migration process.	Phased Migration Gradual migration of users, services, and data will take place. Source domains will remain unchanged, with users transitioning to new target domains.
Need to split users across two tenants My company cannot use the registered (*.onmicrosoft.com) tenant name Moving from a commercial tenant to Microsoft Cloud for Government	Cloud tenant move Identities stay within the source tenant, but all users in the affected domain and workloads are relocated to a new cloud tenant.	Tenant move or split Similar to a single-event migration, but excludes migrating accounts to a new on-premises AD DS forest. This approach is not designed for long-term coexistence, particularly for tenant splits. Migration event includes additional work to re-establish existing identities to the new tenant.

Based on the above scenario you can easily identify the scope and approach of migration. Once you have decided on it, now move to the next step accordingly. 

Now, Let’s Discuss the Most Important Pre-Migration Stage Step By Step

Below is the list of the most crucial pre-planning steps. It ensures data, integrity and security throughout the entire migration process. Go through it before heading to pilot migration. 

Step 1. Domain Preparations

It is crucial to ensure the availability of enough licenses for the target Microsoft 365 tenant. Then, for a smooth and error-free migration, you should also create the respective admin accounts in the source and the destination.

Another very important step to do is, to create the respective user mailboxes, rooms /resources mailboxes, and distribution groups in the destination. You can use the AD DS tools for manual configuration or you can use directory synchronization as well.

Lastly, don’t forget to train your end-users regarding the post-migration changes that they might face in Microsoft 365.

Step 2. Online Domain Verification

The next very crucial step is to verify the respective tenant domain in the M365. To do the same, you need to add the source domain in the destination M365 admin center and then you can create TXT records in DNS settings.

There are other ways as well, you can use the domain connect to verify the respective domain or you can the name servers in the Domain DNS settings in the respective registrar. It can take time to reflect the changes, depending upon the method you have selected, it can vary from 30 min to up to 72 hours for the changes to reflect.

Step 3. Scheduling Your Tenant Migration

Start by creating a CSV file, that contains the list of respective user mailboxes that are to be transferred. It will later be used for group mapping or bulk migration. Then, disabling the directory sync is also an important step to avoid any modifications in the source tenant account AD-DS to the Office 365 platform.

Step 4. Prepare the Source Tenant

We need to remove the primary mail domain from the source tenant before initiating the migration process. To accomplish this task, we need to reset the default email address to the initial email address of Microsoft Office 365.

Then, using the Lync Admin Portal, we need to remove all the respective Lync licenses from the source tenant. Moreover, secondary email addresses must be removed from all tenant objects.

We can use the Windows PowerShell command i.e. Get-MsolUser -DomainName abc.com. It will retrieve all the objects still using the source email or denying the removal.

Step 5. Prepare the Destination Tenant

Follow the below-guided instructions to prepare the destination tenant accordingly:

• In the very first step, we need to configure the auto-discover CNAME.
• Create new user accounts, in the destination domain and assign the required licenses.
• We need to change the mail routing and point the MX record to the new Office 365 email address if the user mailbox is still active.
• Lastly, we need to test the email flow for receiving and sending from the target tenant.

What Does Microsoft 365 Tenant Include and What to Migrate?

A Microsoft 365 tenant includes a variety of apps which depends upon the Office 365 subscription plan you choose. For instance, if you have chosen Microsoft 365 Business Basic Plan then your Microsoft 365 tenant will include the following apps and services:

• Exchange Online
• SharePoint
• Outlook 365
• OneDrive for Business
• Word
• Excel
• PowerPoint
• Microsoft Teams
• Bookings
• Forms
• Lists
• Planner

Now the point here is, what to migrate since you are migrating the complete tenant data, you should migrate Outlook 365 mailbox, OneDrive for Business, Teams, SharePoint, etc.

With this workload, you have two options whether you perform Office 365 tenant-to-tenant migration through manual technique, or you choose software. If you choose the manual method then you have to migrate each software data separately. It’s like moving each box in your house one by one. It can take a while, and you’ve got to be careful not to drop anything.

On the other hand, if you choose the mentioned software solution, then you can migrate the entire workload altogether. It’s like hiring movers who can take all your stuff together. This way, it’s faster, and there’s less chance of things getting lost or broken. Which reduces human efforts and the chances of data loss scenarios. 

Invest in the Reliable and Error-Free Professional Utility for M365 Tenant-to-Tenant Migration

For those who are new to the migration arena, or undergoing it for the first time let’s make it clear that there is no direct manual workaround available to execute this task. Furthermore, Microsoft does not offer any software or steps to migrate the entire data successfully. Hence, many IT admins and migration experts suggest a secure and efficient migration software such as SysTools Office 365 to Office 365 Migration Tool. 

You can download the software from below:

Download Now Purchase Now

You might be thinking – Why go for software? That is because even Microsoft itself suggests that you should use trusted software to perform this task securely. 

Since it is not only about a successful process to migrate Microsoft 365 tenants to another tenant, the need to keep the data safe is also a major concern. If the software you use is migrating the data without any pause, but the data is lost during the process, what is the point of using the solution?

Highlighted Features of the Utility That Helps in Microsoft 365 Tenant Migration

• Allows migration of all the items like Emails, Calendars, Contacts, Documents, etc.
• Enable admins to migrate entire or selective user account mailboxes.
• Offers a Date-range filter to migrate selective data from a certain period.
• Use the Delta Migration feature to migrate newly arrived data after the first process.
• Option to set account-based priorities for migrating certain accounts before others.
• Facility to import CSV files to add Source and Destination mailbox users.
• Shared mailbox migration is also supported by the software.
• Works on Windows 10 (64-bit) and Windows Server versions 2012 and 2016.

Before learning the steps, find the prerequisites as described.

Pre-Requisites for Migration Between Office 365 Tenants via Tool

There are certain prerequisites of the tool that you should know and fulfill before moving to the steps. These requirements are:

• Before migration, ensure that the destination user(s) is already created at the destination admin account.
• You should have application registration in MS Azure Active Directory and the API permissions for source and destination must be enabled.
• The activation code is needed for the tool to perform the process.
• The admin account should have the assigned license for Microsoft 365.

Software Working to Perform Tenant-to-Tenant Migration in Microsoft 365 Step-By-Step

Step 1. Launch the software and in the Setup tab, select Office 365 for both the Source and Destination accounts.

Step 2. Here, choose the categories that you want to export and set the date filters for each in the Workload Selection field.

Step 3. Enter the credentials for your Office 365 account in the Source Window. Press the Validate button and Next.

Step 4. Fill in the details for the Destination Office 365 account and validate it. Hit Next to move further.

Step 5. Choose the Fetch Users or Import Users option to add mailbox users and perform Microsoft Office 365 tenant-to-tenant migration.

Step 6. Complete the process by setting priorities for accounts, mapping the source and destination user accounts, and hitting Start Migration.

In case there are certain files that you may have received during or after the process, you have the option to export only those items.

Mark the Delta Migration option, which will re-scan the mailbox again for any newly arrived data. If there is any new file, the tool will export only those files. Moreover, this tool also assists you in moving a domain between Office 365 Tenants.

Users Should be Aware of These Issues and Challenges

• The very first concern for business organizations having multiple Office 365 domains, is that they require their coexistence at a stretch. Then, it becomes a tough and tedious process to perform a migration between tenants.
• Businesses have tons of data for users, emails, and other mailbox categories. In this scenario, data migration can not be accomplished instantly. Hence, to ensure a smooth data transfer by migration teams, organization employees need to inform and collaborate with others by scheduling a meeting.
• One of the biggest challenges while performing tenant-to-tenant migration in Microsoft Office 365 is to ensure data integrity. They get stuck when they do not ensure the source email data is properly before migration.
• It can create data loss and data corruption when migrating data from older versions of MS Exchange such as 2003 and 2007. As it has a limit on mailbox size of 2GB, when it exceeds the limit, it could lead to data loss.

The above-listed points are only some of the few issues and challenges that can occur while performing this operation. One can face various issues and complications while performing the above operation without any preparation and planning. 

Best Practices to Follow Before Tenant-to-Tenant Migration

1. Examine the Actual Need and Scope of the Migration – In situations where an organization needs to undergo mergers and acquisitions, processes, and communications become quite limited. And eventually, all the intense pressure goes to the IT department to perform this data transfer as soon as possible. “Hurrying will cause problems” Remember this famous quote while executing the migration process. It is quite important to take time to plan and execute the whole process more systematically.  Moreover, make sure to make a list of items to migrate, such as emails, contacts, calendars, documents, or everything together depending on the firm’s respective needs.
2. Back-Up the Current Source and Destination Environments – Backing up your current source and destination environment is vital before proceeding toward Office 365 tenant-to-tenant migration. It always works as an insurance policy – As data migration is a technical and complex process to hands-on. Therefore, just in case anything goes wrong with the migration operation, then it can save your organization’s crucial data. It will ensure a smooth flow of business activity and communication with minimum disruption.
3. Create a Comprehensive Inventory Analysis of Your Source Environment – This is another best practice to create a complete inventory of the source and the destination target environment before migrating from one M365 tenant to another. You should be aware of what to migrate and what to leave behind with all the user account data sizes they have, including email and OneDrive. Once you complete this step, then there is nothing more important left behind.
4. Now It’s Time to Plan the Migration – Once you determine the number of data and user accounts that need to be migrated, then it’s time to plan the migration process. The organization should also be aware of the downtime involved in this process. And mostly they cannot afford the downtime that it may take. As it can hamper the running of business activities. Therefore, phase migration would be the best option to do hands-on as you can determine the user work productivity throughout the whole migration process. Regardless of whether the user’s data is being migrated or not. They would be able to communicate and continue using their Office 365 email account, keeping the whole migration process invisible (in the background) to users of the organization.
5. Effective Communication Before, During, And After Migration – It is the most important best practice to have effective communication throughout this migration in Microsoft 365 tenants process to encounter any error that may take place. Employees must be informed of the different working scenarios that might occur. IT managers need to manage all the licensing requirements that may happen.
6. Make Sure to Monitor and Report on the Real-Time Migration Process – In the list of best practices for Microsoft 365 tenant-to-tenant migration, this is the 2nd last point to remember and follow. You should ensure an appropriate way to monitor the status of the whole migration process in real-time, coordinate with other users and activities, and detect any errors encountered. Moreover, if you want an error-free and efficient migration, you should also check out the complete pre & post-migration checklist for Microsoft Office 365 here.

In Brief

The Microsoft 365 tenant-to-tenant migration procedure is a difficult operation that needs to be handled with care but with this guide in place, you’ll get through it with flying colors. If you perform this task using any tool that is not certified, you may end up losing your data. Hence, to keep the data safe and have an effortless yet successful migration procedure, the above-mentioned tool is the best. Because it is recommended by several migration experts and professionals.

Frequently Asked Questions 

Q1 . How do I easily perform Microsoft 365 Tenant to Tenant migration step by step?

This step-by-step guide will help you migrate Office 365 to a new tenant, using the automated solution (suggested in this blog). As there is no direct or simple manual solution available for this task, we are using the above-mentioned software and performing this task in just 5 steps.

• Step 1. Download, install, and launch the software.
• Step 2. Pick platforms such as Office 365 as source and destination.
• Step 3. Enable required mailbox items and set date filters.
• Step 4. Login with valid credentials and validate permissions.
• Step 5. Create mapping, select users, and start migration.

Q2. Can I migrate the user’s mailbox (emails, contacts, calendars, tasks), admin mailbox, and shared mailboxes from the source Office 365 Tenant to the destination Tenant?

Yes, with the help of a given solution, you can easily migrate mailboxes between M365 Tenants.

Q3. What is a Microsoft Office 365 tenant?

When you create a Microsoft 365 tenant, it becomes a center of services allocated to your organization. In addition to this, it gets registered with two different DNS entries by default for example –  if the tenant name is ABC, then DNS entries will be : 

1. abc.onmicrosoft.com
2. abc.sharepoint.com

A tenant serves as an isolated container for different subscription plans and the licenses assigned within them for respective user accounts. When you set up the tenant, you can assign it to a particular geographical location. One can have multiple geographical locations set up in a single tenant and can also move them based on their needs. To keep your tenant ready for users, groups, licenses, and cloud apps, it becomes crucial to prepare and perform your tenant configuration carefully.

Q4. What is o365 tenant-to-tenant migration?

A tenant-to-tenant (T2T) M365 migration transfers data and resources such as users, mailboxes, Teams, SharePoint, OneDrive data, etc to the destination M365 tenant. Business Mergers, Divestitures, and Acquisitions are some of the main reasons for M365 tenant migration. However, you can not perform Office 365 tenant-to-tenant migration without a tool, and hence, a reliable tool is mentioned above.

Q5. Why do tenants migrate to tenants in M365?

In an organization managing, multiple tenants of the Microsoft 365 suite becomes a monotonous and cumbersome task for IT admins. Utilizes the maximum IT resources and staff for ensuring different permissions, and licenses, and performing other day-to-day activities. To get rid of this, various businesses tend to migrate their tenants to another or single tenant.  

Q6. Where is my Microsoft tenant located?

You can find and view your tenant information by following the below steps:

• Step 1. Log in to your Office 365 account and go to the Microsoft 365 Admin Center. Navigate to Settings. 
• Step 2. Now, click on Org Settings and then click on the Organization Profile tab. 
• Step 3. Then click on  Data location, Here you can see all the data related to your tenant such as the location of data, etc.

Q7. How much time does it take to perform Microsoft 365 tenant-to-tenant migration?

Migration time depends upon various things such as – data size that needs to be migrated, host machine configurations, internet bandwidth, etc. Hence, answering such a query certainly is not possible. On average, it could take up to two weeks to migrate a batch of not more than 1,000 mailboxes.

Q8. What are some common challenges faced during Microsoft 365 tenant-to-tenant migration?

A user can face several challenges during the migration process if the planning is not done properly. 

Some of them are as follows: 

• Data integrity and security concerns
• Business Downtime and communication halt
• Communication downtime for users
• Time taking complex configuration changes
• Potential data loss scenarios

Q9. Is it possible to schedule the migration process to minimize downtime for users?

Yes, it is possible to schedule the migration process to minimize downtime for users. Planning migrations during non-business hours or weekends can help reduce the impact on users. 

Furthermore, if you utilize the above software then you can migrate data anytime without impacting the users. 

Q10. Are there any specific prerequisites or preparations required before initiating a Microsoft 365 tenant-to-tenant migration step-by-step?

Yes, there are several prerequisites as mentioned above, such as verifying domain ownership, setting up DNS records, ensuring proper licenses, and assessing the source tenant’s data for compatibility with the target tenant.

Q11. Are there any limitations or restrictions when migrating data between Office 365 tenants?

Yes, there can be various limitations and restrictions, such as

• You can not migrate certain data types.
• Large data volumes require more time. 
• Potential limitations of the migration tool being used. 

This is why it is suggested to download Office 365 emails locally before the migration. However, you can overcome all these limitations by leveraging the above software solution. 

Q12. Is it necessary to inform users about the migration, and what kind of communication do you recommend?

Yes, it is crucial and highly recommended to inform users about the migration in advance. Clear and timely communication, including emails, notifications, and training if necessary, helps minimize disruptions and ensures a smooth transition.

Q13. What happens to the existing email routing and DNS records during the migration process?

You must update DNS records to point to the new destination after the migration. Additionally, you also have to adjust the email routing configuration to ensure correct email delivery to the mailboxes in the target tenant. 

Once, the migration is complete, the user can update the DNS records, and run the delta migration to migrate the data arrived during the initial migration to ensure 100% data migration without any data loss.