How to Perform Office 365 Tenant to Tenant Migration?

Migrating data between Office 365 tenants is an essential process for organizations undergoing mergers, acquisitions, or restructuring. Before diving into the technical concepts, let’s first define what exactly is an Office 365 tenant-to-tenant migration. A tenant-to-tenant migration involves transferring data such as emails, files, and user accounts from one Office 365 environment to another while ensuring minimal disruption to operations.

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.

Table of Content:

• Introduction
• How to Prepare for Your Office 365 Tenant-to-Tenant Migration?
• Steps for Migrating from One Tenant to Another in Office 365
• Key Steps for Post-Migration Success: Microsoft 365 Tenant Migration Assessment
• Different Architecture Approaches for Microsoft Tenant-to-Tenant Migration
• What Are the Challenges in Office 365 Tenant-to-Tenant Migration?
• Connect with Apps4Rent to Simplify your Office 365 Tenant-to-Tenant Migration
• FAQs Related to Office 365 Tenant to Tenant Migration

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.

How to Prepare for Your Office 365 Tenant-to-Tenant Migration?

It is recommended that users begin preparing for the migration two weeks in advance. Listed below are the key points to consider while planning your tenant-to-tenant migration:

• Prepare the source and target/destination tenants
• Create a CSV file of user accounts
• Create users in destination tenants
• Start the tenant-to-tenant migration in Office 365
• Prepare the domains for accounts being migrated
• Remove the domain from the source and add it to the destination
• Stop mail flow to the source tenant and add new DNS records to destination tenants
• Do the final sync once DNS records are updated
• Cleanup after completion of the migration project

Your 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.

Single Target Tenant: This is the most common type of Office 365 tenant-to-tenant migration. It’s 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.

Multiple Target Tenants: 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.

Steps for Performing Tenant to Tenant Migration in Office 365

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.

If these steps seem overwhelming or if you’re unsure of your ability to execute the migration, consulting a trusted migration professional like Apps4Rent is highly recommended. Our expertise can help you plan and execute a seamless transition tailored to your business needs.

To assist you further, follow the step-by-step guide provided below. 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.

• Assessment and Pre-Migration Planning

  The first step of any Office 365 migration, 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.

• Preparing the Target Tenants

  The next step is to prepare the target tenant 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 consolidation or manually from the Microsoft 365 admin center.

• User Accounts Preparation

  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’ email addresses.

• Moving Objects to the New Accounts

  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, cutover migration, and hybrid migration which have been discussed in another blog. Use the appropriate method depending on the number of Office 365 tenants and the Exchange Server.

• Preparing the Domain

  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’s 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.

• Office 365 Tenant to Tenant Migration Day Activities

  If you have planned your Office 365 tenant to tenant migration well, there aren’t too many activities to be performed on the day of the migration. Broadly, there are only four things to be done.

  • Stop receiving incoming emails to the source tenant.
  • Configure the source tenant domain to move to the target tenant.
  • Verify the source tenant’s domain on the target domain.
  • Select the best migration method and proceed with Office 365 tenant to tenant migration.

• Stopping Inbound Emails

  The migrating server must deliver a “not reachable” 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.

• Updating Mail Exchanger (MX) Records

  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’s 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.

• Disabling Azure Active Directory Syncing

  The Azure Active Directory, which allows access to public folders, apps like SharePoint Online, 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.

• Source Tenant Domain Preparations

  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.

• Target Tenant Reception Preparation

  Once the source tenant domain has been added to the target domain, the transfer has to be verified in the latter’s 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.

Key Steps for Post-Migration Success: Microsoft 365 Tenant Migration Assessment

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.

• Data Integrity and Accessibility Verification: Confirm that all data, including emails and SharePoint sites, 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.
• Update User Configurations: Ensure that user Outlook profiles are updated to the latest email addresses and locations.
• Verify Mail Flow and DNS Records: 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.
• Communicate with Users: 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.

Following these steps will help smoothen the transition process and address any issues that may arise post-migration.

What Are the Different Architecture Approaches for Microsoft Tenant to Tenant Migration?

There are several approaches for Microsoft 365 tenant-to-tenant migration, each catering to specific business scenarios and migration requirements. Here are those common approaches:

• Single Event Migration: The single event migration involves moving all users and data from the source tenant to the target tenant in a single operation. This means that all mailboxes, files, SharePoint sites, and other data are migrated at once, and users are switched from the source to the target tenant on a specific planned date and time.
• Phased Migration: It involves moving users, services, and data from one tenant to another tenant in a gradual manner. This method aims to minimize risks and disruptions during the migration process by spreading it over an extended timeline. Instead of transferring the entire source domain to the target domain at once, the migration is carried out in phases, allowing users to adapt to the changes more smoothly.
• Tenant Move or Split: It is a migration approach used in scenarios where organizations need to move their entire tenant including user accounts, services, and data from one domain to another domain. However, unlike single-event migration, this method does not involve migrating accounts to a new on-premises Active Directory Domain Services (AD DS) forest.

What Are the Challenges in Office 365 Tenant to Tenant Migration?

Office 365 tenant-to-tenant migration comes with various challenges, which can make the process complex and time-consuming. Some of the common challenges include:

• Data Migration Complexity: Transferring large amounts of data, including emails, files, SharePoint sites, and OneDrive content, while maintaining data integrity and metadata can be complex and time-consuming.
• Compliance and security concerns: Ensuring data security and compliance during the migration process is essential, especially when dealing with sensitive information and regulatory requirements.
• Licensing and subscription management: Transferring licenses and managing subscriptions between tenants can be complex, especially if different subscription plans are involved.
• Data loss and data mapping: There is a risk of data loss during the migration if the process is disrupted due to power cut-offs or network issues. Additionally, mapping data from one schema to another in the target tenant requires careful consideration.
• Third-party applications and integrations: Migrating data and services connected to third-party applications can pose compatibility issues, requiring additional configuration and adjustments.
• Downtime and Business Continuity: Minimizing downtime during the migration process is crucial to ensure smooth business operations. Users and admins need to prepare for possible service interruptions while transferring data and applications between tenants.

Apps4Rent Can Help to Migrate from One Office 365 Tenant to Another

For Microsoft 365 tenant-to-tenant migration, thorough planning, and execution are essential to ensure a smooth transition of your organization’s data, applications, and services. Even the most competent IT teams with the best tools available may encounter challenges that require expert assistance to find optimal solutions. That is where Apps4Rent comes in.

As a Microsoft Solutions Partner, Apps4Rent has more than 16 years of experience in migrating emails, calendars, task management files, contacts, and several types of files from other sources to Office 365 and can help businesses in Office 365 tenant-to-tenant migration process without any data loss by using tested tools and methodologies. Our certified Microsoft experts are available 24/7 via phone, chat, and email to help you.

Click here to find out more about our Microsoft 365 tenant-to-tenant migration services

FAQs Related to Office 365 Tenant to Tenant Migration

1. What is a Microsoft Office 365 tenant?
   A Microsoft Office 365 tenant is a dedicated, isolated instance of Office 365 that an organization uses to manage its users, services, and data. It is essentially the container that holds the entire suite of Microsoft services, including Exchange Online, SharePoint Online, OneDrive for Business, and Teams, among others. Each tenant is unique to the organization and is identified by a domain name.
2. What is Office 365 tenant-to-tenant migration?
   Office 365 tenant-to-tenant migration is the meticulous process of transferring diverse data, including emails, files, SharePoint sites, and other content, from one Office 365 tenant to another.
3. Why do organizations opt for Office 365 tenant to tenant migration?
   Organizations opt for tenant to tenant migration to effectively manage pivotal scenarios like mergers, acquisitions, renaming/rebranding or tenant consolidation, aiming to reduce costs and streamline operational complexities in their day-to-day activities.
4. What is the recommended timeframe for planning a tenant-to-tenant migration?
   For a smooth transition, it’s recommended to initiate the migration planning process at least two weeks prior to the intended date. This proactive approach helps mitigate unforeseen disruptions.
5. What are the key steps involved in Office 365 tenant to tenant migration?
   The comprehensive process encompasses preparing both source and target tenants, creating a CSV file listing all user accounts, migrating user accounts and objects, preparing the domain, halting mail flow to the source tenant, updating DNS records, and culminating in a final sync. Detailed insights into this process can be found in the article on O365 tenant to tenant migration setup provided above.
6. How is the domain prepared for migration in Office 365?
   The domain is meticulously prepared by integrating the source tenant into the target tenant’s Microsoft 365 admin center, creating TXT records for DNS verification, and allowing ample time for DNS records to propagate.
7. What are the key activities on the day of Office 365 tenant-to-tenant migration?
   On migration day, crucial activities include halting incoming emails to the source tenant, configuring the source tenant domain for relocation to the target tenant, verifying the domain on the target, and selecting the appropriate migration method.
8. How is the disruption in mail flow minimized during migration?
   Disruption in mail flow is minimized by stopping incoming emails to the source tenant and updating Mail Exchanger (MX) records with the least possible Time to Live (TTL) value.
9. What is the significance of disabling Azure Active Directory syncing?
   Disabling Azure Active Directory syncing is paramount to prevent new changes in the source tenant from affecting the migration process. It’s a crucial step that should ideally be initiated, possibly on a non-working day.
10. What steps are involved in preparing the source tenant domain post-migration?
    Post-migration, the source tenant domain undergoes meticulous handling, involving the reset of SharePoint Online public websites, adjustment of email addresses, removal of secondary emails, and revocation of licenses.
11. How is the target tenant prepared to receive migrated data?
    The target tenant is prepared by adding the source tenant domain to the target domain, verifying the target tenant in the admin center, configuring Azure Directory for the new domain, and assigning licenses to users for mailbox activation.
12. What steps should be taken for Outlook Auto-Complete List post-migration?
    Ensuring successful email deliveries post-migration involves clearing the Outlook Auto-Complete List, which caches the list of addresses to which users send emails.
13. What are the different architecture approaches for Microsoft 365 tenant-to-tenant migration?
    Common approaches include Single Event Migration, Phased Migration, and Tenant Move or Split, each tailored to specific business scenarios and migration requirements.
14. What challenges are associated with Office 365 tenant-to-tenant migration?
    Challenges encompass data migration complexity, compliance and security concerns, licensing and subscription management, data loss and mapping issues, and compatibility issues with third-party applications.
15. How can Apps4Rent assist in Office 365 tenant-to-tenant migration?
    As a Microsoft Solutions Partner with over 16 years of experience, Apps4Rent offers expert assistance in planning and executing migrations, ensuring a seamless transition.