Office 365 Tenant to Tenant Migration: Ultimate Guide

Understanding Tenant to Tenant Migration in Microsoft 365

Like a landlord has multiple residents in his building, similarly, a parent Microsoft 365 account has several child accounts known as tenant accounts. These are of different domains managed under one single space and have hard security and identity boundaries. 

Furthermore, the tenant to tenant migration means moving data from a source account to another target account, including:

• O365 Exchange Online mailboxes 
• OneDrive Business data 
• Online sites of SharePoint
• All chats, channels, and files from Microsoft Teams
• User IDs and domain mapping within M365 

The need for this migration can arise at anytime, and it has several reasons stated further in this section. 

Why Office 365 Tenant to Tenant Migration is Important?

There are various substantial reasons for this migration, discussed as follows:

• During company mergers and acquisitions, consolidating data of tenant accounts into one is needed. 
• Optimizing the cost for maintaining old and new tenant accounts can be a reason for migration. 
• Revamping the company’s domain name or names during the switch demands this migration for rebranding.
• To adapt the new policies and regulations of the new tenant account, this migration is essential. 
• The universal desire to expand and increase development and flexibility in the company demands this migration. 

Getting to know these justifications helps in a secure and ordered data migration with complete procedures and no risks. 

Which Practices Move Office 365 Tenant to Tenant Safely?

This section explores the manual procedure and an automated software for a quick and reliable migration. With the manual method, you may need to fulfill some prerequisites, and also, since it is free, there are many limitations and complexities involved. Let’s understand them one by one. 

Native Office 365 Tenant to Tenant Migration

M365 tenant to tenant migration is possible primarily for Exchange Online mailboxes. Yet, the process requires careful planning, technical skills, and execution. It is divided into several parts (pre-migration→ migration→ post migration) process. You can follow these steps:

Step 1: Assessing and Preparing Tenant Accounts 

1. Initially, identify the source and target tenant accounts and confirm admin access for both accounts. 
2. Next, list all the users, mailboxes, domains, and their Exchange Online licences. 
3. After that, check the existing custom domain and subscription to your Office 365 account. 
4. Also, verify the litigation hold, compliance policies, and retention controls. 
5. Moreover, ensure to lower the DNS TTL value 24-48 hrs before the migration.
6. Once done, remove the custom domain from the source tenant account. 
7. Add and verify the domain in the target tenant account within O365. 

8. Assign the users with onmicrosoft.com addresses temporarily as required. (optional)

Step 2: Configuring Cross-Tenant Relationships 

To ensure explicit trust and absolute organizational relationships between Microsoft tenants:

1. Within the O365 Azure AD account, move to External Identities.
2. There, configure the cross-tenant settings and allow B2B collaboration. 
3. Next, establish the relationships within Exchange Online PowerShell. 
4. Finally, allow the permissions for mailbox replication.

Step 3: Creating Migration Endpoints and Mapping Mailboxes

1. Use Exchange Online PowerShell to create migration endpoints in the Office 365 Admin Center. 
2. Authenticate the endpoints with global admin credentials and validate connectivity for secure migration.
3. Then, in the Exchange Admin Center, go to Migration, and choose Create Migration Batches. 
4. Define the new batches for migration, assign them a name, assign endpoints, and map the mailboxes. 
5. Further, create a CSV for mailbox mapping with the following details:

• User addresses for the source and target tenant accounts
• Exchange Online licences for the specific tenants

6. Once done, click Start Migration to initiate the mailbox sync and begin the process. 

Step 4: Finish Migration and Switch Mails

1. After the synhronization established and the migration is finalized, update the MX records. 
2. Point them to the target tenant account and validate email delivery and integrity of the mailbox. 
3. Once everything is successfully verified, decommission the source tenant account. 

Why Manual Method is Not Considered Optimal?

Despite being free, this method is very lengthy, complex, time-consuming, and requires a high level of technical expertise. Also, it doesn’t handle the large tenant mailboxes well. Moreover, data for many services like OneDrive, SharePoint, Planner, and Microsoft Teams is not moved appropriately. 

Besides this, there are high chances of human errors and risk of data loss due to:

• Incomplete or incorrect mailbox mapping 
• Blocked items due to active retention policies
• Domain mismanagement and improper validation 

Therefore, it is better to look for a more flexible, reliable, secure alternative like the one below. 

Smart Office 365 Tenant to Tenant Migration

While the manual method is available for the migration, it is not suited for large-scale tenant migrations. To balance the control, migration speed, and risk management, use the SysInfo Office 365 Migrator Tool. This software enables all technical and non-technical users, including beginners, to securely and actively migrate data with zero loss. 

Steps for Microsoft 365 Tenant to Tenant Migration

1. Start the Office 365 Migrator Software and click Backup. 
2. Then, choose a mode of authentication, input source tenant account credentials, and tap Sign In. 
3. Afterward, select the source mailboxes and the user accounts and click Next. 
4. Furthermore, choose folders from the mailbox hierarchy and click Next. 
5. Later, opt for Office 365 from the menu, pick an authentication mode, and enter the target tenant account credentials. 
6. Complete the sign-in, apply the filters from the software, and click Next. 
7. Map the source and target tenant accounts in the map user panel and click Next. 
8. At last, check the destination mailboxes of each tenant and click Backup to complete the process. 

Why is Tool Ideal for Office 365 Tenant to Tenant Migration?

Though it is paid, this software provides the following benefits:

• Allows bulk migration of data from the source Office 365 tenant account in one go. 
• Ensures complete data and folder structure preservation during the tenant to tenant migration. 
• User-friendly software with automation and no complex migration procedures. 
• Transfer all M365 emails, attachments, tasks, notes, contacts, calendars, OneDrive, SharePoint, and other data.
• Great compatibility for all the recent and older versions of Windows and Mac OS. 
• Supports direct tenant to tenant migration in Microsoft 365 with secure OAuth authentication. 
• Has multiple filter options for duplicate removal, selective conversion, attachment handling, and folder naming. 
• Equipped with a Demo Version for conversion of upto 50 emails per folder at no cost. 

Conclusion

M365 Tenant to Tenant Migration is the center for identity, compliance, trust, and Office collaboration among multiple teams. Hope this guide helped you out with the Office 365 tenant to tenant migration in an efficient and complete way. Manual migrations are feasible, but only when you are a techie expert or have a lot of time with a small mailbox. For large tenant migrations in a sound manner, saving time, cost, and effort, using the professional Office 365 Migration Tool is the best choice. 

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About The Author:

Deep Shikha

Deep Shikha Pandey is a Tech Writing Expert having deep knowledge about Outlook, Gmail, Yahoo, SQL, and other databases and email clients. She will guide you the best about email migration and SQL Database recovery using her expertise and making all the processes a cakewalk for the readers. Make your technical journey easy with simple layman’s blogs and accurate technical information.