Migrating data between Office 365 tenants is an essential process for organizations undergoing mergers, acquisitions, or restructuring. Before diving into the technical concepts, let\u2019s first define what exactly is an Office 365 tenant-to-tenant migration. Commonly referred to as an O365 tenant to tenant migration or M365 tenant to tenant migration, this process involves transferring data such as emails, files, and user accounts from one Microsoft 365 environment to another while ensuring minimal disruption to operations.<\/p>\n
This guide provides a detailed, step-by-step approach to help you navigate the complexities of the migration process effectively and securely. Whether you’re moving a few users or an entire organization, proper planning and execution are key to a successful migration.<\/p>\n
Often, organizations have to deal with multiple Office 365 accounts in situations like mergers and acquisitions. In other scenarios, consolidating tenants on different versions within the same organization may be necessary to streamline operations and reduce both costs and complexity. This article will provide an overview of how Office 365 tenant-to-tenant migration works, along with a concise outline of the key steps businesses must follow when executing this type of migration.<\/p>\n
Key Takeaways<\/p>\n
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- Office 365 tenant-to-tenant migration moves mailboxes, Teams, SharePoint, and OneDrive data from one Microsoft 365 tenant to another, most often for mergers, acquisitions, or tenant consolidation.<\/li>\n
- Most migrations take 2 business days to 8 weeks, depending on user count and how many workloads are involved.<\/li>\n
- Typical cost runs $100 to $150 flat for 1 to 5 mailboxes, plus $40 to $80 per mailbox beyond that, though heavy SharePoint or Teams migrations usually need a custom quote.<\/li>\n
- Common tools include Microsoft’s native cross-tenant migration feature, BitTitan MigrationWiz, ShareGate, Quest On Demand, and AvePoint Fly.<\/li>\n
- The three main architecture approaches are Single Event Migration, Phased Migration, and Tenant Move or Split.<\/li>\n
- Start planning at least two weeks ahead, and disable Azure Active Directory (Microsoft Entra ID) syncing on a non-working day to avoid mid-migration changes.<\/li>\n<\/ul>\n<\/div>\n\n\n
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\n Call 1-866-716-2040<\/a>\n <\/div>\n<\/p><\/div>\n<\/div>\nHow to Prepare for Your Office 365 Tenant-to-Tenant Migration?<\/h2>\n
Start planning your Office 365 tenant to tenant migration at least two weeks in advance: prepare both tenants, map users, and stage DNS changes before cutover.<\/strong> It is recommended that users begin preparing for the migration two weeks in advance and also include an Office 365 tenant setup checklist during this preparatory period. If you want a broader planning reference beyond tenant consolidation scenarios, our Office 365 Migration Checklist<\/a> covers pre-migration, migration day, and post-migration steps in more depth. Listed below are the key points to consider while planning your tenant-to-tenant migration:<\/p>\n
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- Prepare the source and target\/destination tenants<\/li>\n
- Create a CSV file of user accounts<\/li>\n
- Create users in destination tenants<\/li>\n
- Start the tenant-to-tenant migration in Office 365<\/li>\n
- Prepare the domains for accounts being migrated<\/li>\n
- Remove the domain from the source and add it to the destination<\/li>\n
- Stop mail flow to the source tenant and add new DNS records to destination tenants<\/li>\n
- Do the final sync once DNS records are updated<\/li>\n
- Cleanup after completion of the migration project
![\"Steps](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2025\/01\/Steps-for-Preparing-Office-365-Tenant-to-Tenant-Migration.png\")
<\/li>\n<\/ul>\nYour needs might also differ based on the nature of the migration you are undertaking. Tenant-to-tenant migrations can involve moving data from your source tenant to one or multiple destination tenants, each having its advantages and challenges. For a detailed comparison, you can also explore our guide on single vs multiple tenant Microsoft Office 365 migration<\/a>.<\/p>\n
Single Target Tenant:<\/strong> This is the most common type of Office 365 tenant-to-tenant migration. It\u2019s simpler than migrating to multiple target tenants and all the users are, as the name suggests, transferred to the same tenant. Single-tenant migrations are less work and easier to perform and secure.<\/p>\n
Multiple Target Tenants:<\/strong> This method of Office 365 tenant-to-tenant migration is generally carried out by larger organizations having multiple teams or those operating from several locations. In this approach, users from the source tenant are moved to several destination tenants. The key difference between the two is in the latter approach users from one tenant will be guests on the other. This complicates cross-tenant collaboration and makes it harder to secure multiple Office 365 tenants due to the guest permissions involved.<\/p>\n
![\"Single](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2025\/01\/Single-and-Multiple-Target-Tenants-in-Office-365-Tenant-to-Tenant-Migration.png\")
<\/p>\nWhat Is Office 365 Tenant-to-Tenant Migration?<\/h2>\n
Office 365 tenant-to-tenant migration is the process of moving mailboxes, files, user accounts, and other Microsoft 365 data from one tenant to another, typically during a merger, acquisition, or IT consolidation.<\/strong> This section explains what is an Office 365 tenant and why tenant-to-tenant moves are needed. Tenant migration is an essential process for organizations undergoing significant structural changes, such as mergers, acquisitions, or restructuring. It involves the transfer of data, users, and services from one Office 365 tenant to another, ensuring minimal disruption to day-to-day operations and a smooth transition for all stakeholders. <\/p>\n
Understanding tenant migration is crucial for maintaining business continuity. The complexities of moving email accounts, documents, and other critical data must be carefully planned to avoid potential interruptions. By adhering to a strategic approach, organizations can ensure that the migration process is efficient, with data integrity intact, and that user access is uninterrupted. <\/p>\n
What Are the Steps for Office 365 Tenant to Tenant Migration?<\/h2>\n
An Office 365 tenant to tenant migration follows five core stages: assessment, target tenant preparation, user and data migration, domain cutover, and post-migration validation.<\/strong> Now you might be wondering, what is the best way to plan for an Office 365 tenant-to-tenant migration. To begin, assess your current environment thoroughly and identify the data and resources that need to be migrated. Create a detailed timeline that includes preparation, execution, and post-migration tasks. Prioritize clear communication with stakeholders to minimize disruptions. Use reliable tools to streamline the process and ensure data integrity.<\/p>\n
If these steps seem overwhelming or if you\u2019re unsure of your ability to execute the migration, consulting a trusted migration professional like Apps4Rent<\/a> is highly recommended. Our expertise can help you plan and execute a seamless transition tailored to your business needs.<\/p>\n
Follow this Office 365 tenant to tenant migration step by step roadmap for assessment, transfer, and cutover. It outlines the key procedures and strategies required to manage and execute an Office 365 tenant-to-tenant migration effectively while reducing potential risks and maintaining data integrity.<\/p>\n
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Assessment and Pre-Migration Planning<\/h3>\n
The first step of any Office 365 migration<\/a>, including tenant to tenant migration, is to plan the migration process well in advance, in most cases, at least two weeks before the scheduled date, to avoid unforeseen disruptions. Planning the process includes taking measures to ensure that the prerequisites for the Office 365 migration are fulfilled and any other licenses for third-party migration tools have been acquired.<\/li>\n
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Preparing the Target Tenants<\/h3>\n
The next step is to prepare the target tenant, which must be configured as part of the Office 365 tenant setup, to migrate mailboxes from the source tenant. This might include creating an additional room in it to accommodate new user mailboxes. The migration process needs admin accounts for both the source and target tenants. Objects like Rooms, Resources, Groups, and Users from the source tenant will have to be created in the Target Tenant through Azure Active Directory (now called Microsoft Entra ID) consolidation or manually from the Microsoft 365 admin center<\/a>.<\/li>\n
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User Accounts Preparation<\/h3>\n
The IT team of the organization must generate a CSV file of the email addresses that have to be migrated to the target mailbox for using a third-party migration tool. It is advisable to append.onmicrosoft.com to the source tenants\u2019 email addresses.<\/li>\n
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Moving Objects to the New Accounts (includes mailboxes, OneDrive and SharePoint site moves)<\/h3>\n
The Office 365 tenant to tenant migration is complete when all objects including calendars and contacts have been moved to the new accounts. There are different methods of migration, namely staged migration<\/a>, cutover migration<\/a>, and hybrid migration<\/a> which have been discussed in another blog. Use the appropriate method depending on the number of Office 365 tenants and the Exchange Server<\/a>.<\/li>\n
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Preparing the Domain<\/h3>\n
The source Office 365 tenant will have to be merged with the target tenant. This is done by adding the source tenant to the target tenant\u2019s Microsoft 365 admin center and creating TXT records for DNS verification. This will allow sufficient time for DNS records to propagate to the new server.<\/li>\n
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Office 365 Tenant to Tenant Migration Day Activities<\/h3>\n
If you have planned your Office 365 tenant to tenant migration well, there aren\u2019t too many activities to be performed on the day of the migration. Broadly, there are only four things to be done.<\/p>\n
For Exchange Online migration between tenants, ensure MX records are updated and mail flow is tested before completing the cutover.<\/p>\n
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- Stop receiving incoming emails to the source tenant.<\/li>\n
- Configure the source tenant domain to move to the target tenant.<\/li>\n
- Verify the source tenant\u2019s domain on the target domain.<\/li>\n
- Select the best migration method and proceed with Office 365 tenant to tenant migration.<\/li>\n<\/ul>\n<\/li>\n
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Stopping Inbound Emails<\/h3>\n
The migrating server must deliver a \u201cnot reachable\u201d message to mail servers that are trying to deliver new mail to it. It is advisable to rope in a third-party service that can queue emails for a pre-decided time during the transition period to prevent a non-delivery report from being sent to the senders.<\/li>\n
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Updating Mail Exchanger (MX) Records<\/h3>\n
The MX records indicate the address of the mail server that receives emails for the Office 365 tenants. When the source tenant migrates to the target tenant, the server address receiving email on behalf of users will have to be changed to the target tenant\u2019s address. Changing the address to which the records point will take time during which period there would be a disruption in the mail flow. This period, called time to live (TTL) has to be kept to the least possible value for minimizing disruption. So, the IT team must run tests to determine the TTL before proceeding with the migration.<\/li>\n
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Disabling Azure Active Directory Syncing<\/h3>\n
The Azure Active Directory, which allows access to public folders, apps like SharePoint Online<\/a>, and other resources must be forced to stop syncing before accounts can migrate from one Office 365 tenant to another. This process can take almost a day and has to be initiated early on. Any new changes in the source tenant will not be reflected once the sync is disabled. Hence, it must be planned accordingly, preferably on a non-working day.<\/li>\n
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Source Tenant Domain Preparations<\/h3>\n
The source tenant domain has to be removed from Office 365 for the migration to succeed. This entails resetting SharePoint Online public websites, email addresses, and other objects back to the initial domain. Secondary emails will have to be removed and licenses have to be revoked before migrating to the new Office 365 accounts. The processes that are blocking the removal will have to be manually stopped using the PowerShell command.<\/li>\n
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Target Tenant Reception Preparation<\/h3>\n
Once the source tenant domain has been added to the target domain, the transfer has to be verified in the latter\u2019s admin center. The Azure Directory has to be configured for the new domain in the target domain and the licenses to be assigned to users for mailbox activation. Assign the old email addresses as the primary addresses and set passwords for them. The inboxes will start receiving mail once the MX record updates are complete.<\/li>\n<\/ul>\n
\n\nManaged Migration<\/p>\n<\/p><\/div>\n
\nLet Apps4Rent Run Your Tenant to Tenant Migration<\/h3>\n
From tenant assessment and user mapping to mailbox cutover and DNS updates, Apps4Rent’s migration engineers handle every step above for you, start to finish.<\/p>\n
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\n Call 1-866-716-2040<\/a>\n <\/div>\n<\/p><\/div>\n<\/div>\nWhat Are Concurrent Migrations in Office 365?<\/h2>\n
Concurrent migrations run multiple migration jobs in parallel to speed up large or time-sensitive Office 365 tenant to tenant migration projects.<\/strong> When planning a Microsoft 365 tenant to tenant migration, concurrent migrations play a critical role in accelerating timelines, especially in high-volume or time-sensitive scenarios. This method involves executing multiple migration jobs in parallel across separate machines or environments, thereby increasing overall throughput and reducing the total duration of the migration. <\/p>\n
Running concurrent jobs is particularly useful in complex Office 365 tenant to tenant migration projects where large user bases, shared resources, and data dependencies require efficient coordination. To ensure a smooth experience, it\u2019s essential to schedule migration waves strategically, balance workloads, and monitor each job in real time. Additionally, using dedicated credentials per migration thread helps prevent throttling, while optimized network configurations reduce latency and avoid performance bottlenecks. <\/p>\n
When executed effectively, concurrent migrations help organizations meet tight cutover windows and maintain control over every stage of the O365 tenant migration process. <\/p>\n
How Do You Migrate Microsoft Teams, OneDrive, SharePoint, and Planner?<\/h2>\n
Migrating Teams, OneDrive, SharePoint, and Planner between tenants works best as a phased process: provision destination Teams first, then move SharePoint and OneDrive data, then chat history and Planner tasks.<\/strong> Successfully migrating collaboration platforms during a Microsoft tenant to tenant migration requires a phased and methodical approach. These workloads are tightly integrated and must be handled with care to preserve permissions, file structures, user access, and communication continuity. <\/p>\n
A standard tenant to tenant migration Office 365 step by step approach starts with provisioning destination Teams and channels. Once the structure is established, migrate associated data from SharePoint and OneDrive, ensuring document libraries, folders, and file metadata remain intact. In subsequent passes, move channel tabs, chat history, and Planner tasks to maintain productivity and historical context. <\/p>\n
To streamline the process, many organizations rely on advanced migration tools that support automation, compliance, retention, and integrity checks. These tools are especially beneficial when undertaking a full-scale M365 tenant to tenant migration, as they simplify execution and help organizations migrate Office 365 to Office 365 tenant with minimal disruption. <\/p>\n
By addressing these workloads, including OneDrive tenant to tenant migration and SharePoint tenant to tenant migration approaches, in clearly defined phases, organizations can confidently migrate from tenant-to-tenant Office 365 while maintaining operational continuity and end-user experience. Organizations using Dynamics 365 should also account for Dynamics 365 tenant to tenant migration as part of the overall project scope, as CRM data requires separate handling from mailboxes and SharePoint.<\/p>\n
What Are the Key Steps for Post-Migration Success?<\/h2>\n
Post-migration success depends on verifying data integrity, updating user Outlook profiles, confirming DNS and mail flow, and communicating the completed migration to users.<\/strong> It is crucial to carry out a post-migration assessment of your tenant to ensure a successful transition and that all systems are functional. We have compiled a list of the most critical post-migration checks to ensure a seamless migration. These steps are to be done in addition to the verification of migrated OneDrive and SharePoint content. <\/p>\n
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- Data Integrity and Accessibility Verification:<\/strong> Confirm that all data, including emails and SharePoint sites<\/a>, have been accurately transferred to the destination tenant. Also, check to see if the data is accessible to all users.Outlook caches the list of addresses to which users send emails. After migrations, there is a possibility that the replies on migrated emails may not be delivered successfully. This issue can be resolved by clearing the Outlook Auto-Complete List.<\/li>\n
- Update User Configurations:<\/strong> Ensure that user Outlook profiles are updated to the latest email addresses and locations.<\/li>\n
- Verify Mail Flow and DNS Records:<\/strong> Possibly the most important item on any Office 365 tenant-to-tenant post-migration checklist is ensuring that all DNS records, including the MX records have propagated correctly. Also, confirm that the email flow points to the new tenant.<\/li>\n
- Communicate with Users:<\/strong> Get in touch with the users and inform them of the completed migration. Provide relevant information regarding account access and offer support for any queries\/issues they may have.<\/li>\n<\/ul>\n
Following these steps will help smoothen the transition process and address any issues that may arise post-migration.<\/p>\n
Also Read:<\/b> How to Perform Cross-tenant Mailbox Migrations?<\/a><\/i><\/p>\n
How Do You Restore the Outlook Auto-Complete List After Migration?<\/h2>\n
You can restore the Outlook Auto-Complete list after migration by using the free MFCMAPI tool to export the AutoComplete cache from the source mailbox and reimport it into the new mailbox.<\/strong> Restoring the Outlook AutoComplete list, a feature that remembers email addresses as you type, can be especially helpful during profile resets, mailbox moves, or Microsoft 365 tenant to tenant migration scenarios. The process involves two main stages: exporting the data from the source mailbox and importing it into the destination mailbox. While technical in nature, the steps are manageable with the right tools and precautions. <\/p>\n
First, use a utility called MFCMAPI to safely extract the AutoComplete data from the user’s existing Outlook profile. This tool allows access to the underlying mailbox properties, including the hidden message where AutoComplete entries are stored. Once located, the AutoComplete cache is exported as a message file and saved locally. <\/p>\n
Next, to restore the data, you’ll use the same tool to reinsert the saved AutoComplete message into the new or refreshed mailbox. It’s important to remove any existing AutoComplete data beforehand to prevent conflicts or duplicates. Once imported, Outlook recognizes the restored data, and users will once again see familiar email suggestions as they compose messages. <\/p>\n
While this isn’t a native Outlook feature, MFCMAPI offers a reliable workaround, particularly valuable during Office 365 tenant to tenant migration or user mailbox transitions within Microsoft 365 environments. Careful execution ensures the user experience is preserved without manual re-entry of addresses, streamlining post-migration usability. <\/p>\n
What Are the Architecture Approaches for Microsoft 365 Tenant-to-Tenant Migration?<\/h2>\n
The three main architecture approaches for Microsoft 365 tenant-to-tenant migration are Single Event Migration, Phased Migration, and Tenant Move or Split.<\/strong> Here are those common approaches:<\/p>\n
![\"Different](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2025\/01\/Different-Architectural-Approaches-for-Microsoft-Office-365-Tenant-to-Tenant-Migration.png\")
<\/p>\n - Update User Configurations:<\/strong> Ensure that user Outlook profiles are updated to the latest email addresses and locations.<\/li>\n
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![\"Microsoft](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2026\/07\/microsoft-native-vs-third-party-migration-tools.png\")
<\/p>\n![\"Office](\"https:\/\/www.o365cloudexperts.com\/blog\/wp-content\/uploads\/2026\/07\/office-365-tenant-to-tenant-migration-timeline.png\")
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