Splitting Office 365 Tenant refers to the process of separating the users, data, domains, and workloads from a single “source” tenant to a new “target” tenant.
This Office 365 tenant-to-tenant migration process is often exercised after divestitures or spin-offs. In other words, when a business asset is being sold or spun off into a new startup.
But it is not as easy as it sounds! It requires ultimate precision because one mistake can manifest into improper migration or significant data loss.
So, to ensure a smooth Office 365 Tenant split after a divestiture, explore this straightforward guide. It will help you in Microsoft 365 tenant split preparation and execution.
Microsoft 365 Pre-Tenant Split Checklist (For IT Administrators)
Do you know that splitting Microsoft Office 365 Tenant or corporate split is considered one of the most puzzling projects in cloud infrastructure? The industry data reflects that 1 in 3 enterprise migrations experience broken dependencies post-migration, resulting in:
- Partial data loss
- Broken authentication
- And, changed permission issues.
Note: Breaking dependencies post-migration is a process of removing the connection between the newly migrated system or app and its legacy (previous) environment.
Seasoned IT administrators who performed tenant splits would agree with us on this!
See, the process of data partitioning (separating users’ data, domains, and workloads) requires a surgical approach. So, as an IT admin, you can refer to the following checklist. These practical pre-migration steps are also the “best M365 tenant split best practices”.
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How to Split Office 365 Tenant? The Four-Step Method!
Here are the straightforward steps to Microsoft Office 365 Tenant split smoothly:
Step 1: Create & Set Up the Target Tenant
The process of splitting the Office 365 tenant begins with creating & setting up the target tenant. So,
- Create a new Microsoft 365 target tenant via a temporary .onmicrosoft.com domain.
- Next, set up the basic security settings, such as Identity Protection and Global Admin Accounts.
- Lastly, provide the same user accounts ( in the target tenant). Use the temporary routing address like [email protected].
Step 2: Prepare the Migration Software
Once the target tenant is set up properly, configure the built-in Microsoft Orchestrator or your migration software. And start initial seeding. To do so,
- Set up the migration tool >> Provide API permissions in both the “Source” and “Target” tenants.
- Start the Initial Pass. It will copy 90-95% of historical data (email, OneDrive, and SharePoint) in the background. During this process, you can work in the source tenant.
Step 3: Lock Out Users, Run Final Pass, and Change Mail Exchanger Record
Now, block sign-in and password changes to stop data generation in the source tenant. And run the final pass to identify any document modification throughout the initial seeding.
Also, change MX (Mail Changer) records to update the public DNS records. It will ensure the inbound emails (emails sent within your organization) don’t shake up while moving the domain.
- To do this, simply direct the mail exchanger (MX) record of the divested domain to a third-party mail-queuing service (Mailgun, Amazon SES).
Step 4: Switch Domain to Another Tenant
The final step of splitting the Microsoft Office 365 tenant is moving the domain from one tenant to another. Here’s how to execute this:
- Remove the custom domain from the source tenant completely (all users, groups, aliases, and distribution lists).
- Next, delete the domain from the source tenant’s portal as well.
- Instantly, sign into the target tenant >> add the custom domain >> verify (via a DNS TXT record).
- Attach the User Principal Names (UPNs) and main SMTP addresses of the target users to the newly created custom domain. This will update the target UPNs.
- Lastly, update the public MX records. And navigate straight to the new Microsoft 365 target tenant.
Real World Pitfalls of Microsoft 365 Tenant Split
Splitting M365 tenant and moving it into a new environment is a complex, layered process. It can overwhelm IT admins who are just getting started with unexpected delays and errors.
Therefore, to anticipate a smooth Microsoft 365 Tenant split, make sure you go through the real-world pitfalls of an O365 Tenant Split. It addresses the common stumbling block experienced by admins and their easy fixes.
#1 Delayed Domain Availability (15 Mins to 4 Hours Void)
Microsoft does not release the domain instantly after the deletion. Generally, it takes anywhere from 15 minutes to over 4 hours to be ready for verification in the target tenant.
The Solution: IT administrators can bypass this void by scheduling domain deletion during the low-traffic windows, such as Friday night. Also, employ a third-party email spooling/queuing service like Mimecast or Proofpoint. It will pause the inbound emails during the void, ensuring that no data is lost.
#2 Microsoft Intune and Device Migration Issues
Laptops and mobile devices managed by Microsoft Intune cannot be migrated via a cloud tool because those devices are securely bound to the source tenant’s Entra ID.
The Solution: Begin by un-enrolling the linked devices from the source tenant. Then, leave corporate management. And lastly, enroll in the new target tenant’s Intune environment.
#3 Outlook Profile Authentication Error
Outlook profile throws authentication errors on the local desktop after moving to the target tenant due to a hidden X.500 routing address. Even creating new Outlook profiles doesn’t fix these errors. Because their “Autocomplete” list (the cached email suggestions) holds the same routing address, it not only directs it to the old tenant but also causes internal emails to bounce.
The Solution: As an IT leader, you can provide users with a script or a definitive tool to automatically set up the new Outlook profile. It will also remove historical autocomplete caches.
#4 Microsoft Teams 1:1 Chat History Unavailability
Do you know Microsoft Teams 1:1 chat data is stored in hidden folders within the Exchange mailbox? Therefore, sometimes splitting the Microsoft 365 tenant and migrating to another could break the continuity of the chat streams. Or, worse, it may fail to move tidily.
The Solution: Re-examine the legal and compliance requirements. If keeping a 1:1 chat is strictly needed, utilize a specific, enterprise-grade tool like Systools Microsoft Teams Migration tool.
One of the most recommended M365 Teams switchers by Office 365 administrators, with an average 4.7/5.0 rating based on 2208 reviews.
- Excels in migrating Personal Chat, Groups, Files, Channels, and even Posts.
- Can move all types of Teams (Private, Public, & Organization). Including Members & Member Permissions.
- Migrates Files/attachments, GIF, Emoji, Announcement, Reply/Conversion.
- This M365 Teams switcher tool also provides an option to create Teams & Channels at the destination automatically.
- It can be accessed on Windows Server 2016, 2019, 2022, 2025, Windows 10/11 (64-bit).
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Post-Migration Support Checklist
Encountering issues immediately after splitting the Office 365 tenant and shifting to a new tenant is quite common. So, here is a post-migration support checklist. It will ensure that your emails flow properly and data is in the preferred destination.
- Direct users to register their Microsoft Authenticator apps in the new environment.
- Also, guide users to resend sharing invitations from the new target tenant. Because external links shared from the source tenant’s SharePoint/Onedrive will not be usable.
- And, external companies are required to remove the old guest accounts. And invite new user identities. (for the users with guest access in the external client tenants).
Best Tool for Tenant Divestiture Office 365
SysTools Office 365 to Office 365 Migration tool is a trusted, enterpsie-grade tool for spliting tenant and migrating to the new tenant. A most-preferred migration tool of IT admins after M365 Tenant Divestiture.
- It is a proficient tools that has successfully migrated 648 Million+ emails, 10 Million+ contacts, 16 Million+ calendars. Including 22 Million+ documents till now!
- This robust tool can also move Teams data, SharePoint sites, and shared mailbox data. Along with personal chats.
- You can also transfer In-Place Archive to Office 365.
- And, it incredibly migrates newly arrived items from souce account using Delta Migration.
- It is alos decorated with an average 4.9/5.0 stars wholly based on 1540 reviews.
Steps to Migrate Tenants
Step 1: Begin by pressing the download button. Once downloaded, open the software.
Step 2: Select “Microsoft 365” (In the “Source” and “Target” section).
Step 3: Enable the Workloads that you like to move (Email, Contacts, Calendars). Next, set a date filter >> press “Next”.
Step 4: Insert Admin Email and APP ID (In the Source window) >> press “Next”.
Step 5: Type out the destination Admin’s Email and App ID (In the Destination window)
Step 6: Give the users (in the Resources Screen) using the given options:
- Fetch them directly
- Import from a pomade CSV
- Or, download the blank template >> upload it with your user list.
Step 7: Lastly, examine the arranged user list >> press “Start Migration”. You can also set a priority to a particular account using the Star option.
Author’s Final Words
Splitting Microsoft Office 365 Tenant is not an easy feat- It can feel burdensome. But if you are mandated to split the M365 tenant after the divestiture, you can always refer to this easy-to-digest guide.
It will act as a trustworthy associate and assist you in all the profound stages:
- Pre-Tenant Splitting
- During Tenant Splitting
- And, Post Tenant Spitting
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FAQs (Frequently Asked Questions)
Q.1 How to split Office 365 tenant?
To split Office 365 Tenant, follow the given steps:
- Create & Set Up the Target Tenant
- Prepare the Migration Software
- Lock Out Users, Run Final Pass, and Change Mail Exchanger Record
- Switch Domain to Another Tenant
Q.2 Can I use native Microsoft Orchestrator to migrate my data?
Absolutely, yes! Microsoft’s Cross-Tenant Orchestrated User Data Migration can migrate Exchange, Teams chats, and OneDrive. It uses a single orchestrator but requires premium licensing and comes with limitations.
Q.3 Why my new Outlook profile showing authentication error?
Your new Outlook profile is showing authentication errors on the local desktop due to a hidden X.500 routing address. Use a script or a specific tool to automatically configure the new Outlook profile. It will also delete historical autocomplete caches.
Q.4 My Teams chats are not migrated properly after migration?
Microsoft Teams 1:1 chat data is tied to hidden folders within your Exchange mailbox. Therefore, sometimes splitting the Microsoft 365 tenant could fail to migrate properly. Always use an enterprise-grade tool for moving Team data.
Q.5 Why can’t I see the domain in the new tenant?
Microsoft takes anywhere from 15 minutes to 4 hours for verification in the target tenant. That’s why you can’t see the domain in the new tenant.
