Microsoft 365 Tenant to Tenant Migration
  • April 5, 2023
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In today’s digital age, businesses constantly seek ways to improve their productivity and efficiency. With many companies shifting towards cloud-based software, Office 365 has become a go-to choice for many organizations. However, with the increasing need for Microsoft 365 tenant-to-tenant migration processes due to mergers or acquisitions, it has become imperative for companies to understand the best approach for a successful migration. While there are manual ways of achieving this process, it can be time-consuming and complicated. In this blog post, we will explore more about mailbox migration between Office 365 Tenants.

A Microsoft 365 tenant consists of a set of services such as Exchange Online, SharePoint Online, OneDrive for Business, and Teams tied together by an organizational account. Microsoft 365 Tenant-to-tenant migrations allow organizations to move their email data and associated services from one Microsoft 365 tenant to another. Using a manual process, you can only transfer mailbox data (emails, contacts, calendars, notes, etc.) between Office 365 tenants.

Need for Mailbox Migration Between Office 365 Tenants

There are several reasons why organizations may decide to migrate their data using T2T migration. For example:

Mergers or acquisitions:

When two organizations merge into one business entity, it is required to move mailbox data from one Tenant to another.


When a company splits into smaller entities, it requires shifting some employees into another company and transferring their data.


When an organization undergoes rebranding in which its domain name changes, it must move mailbox data to a new domain or Tenant.


In some cases, legal requirements may mandate data transfer between Microsoft 365 tenants.

Steps Need to perform Microsoft 365 Tenant to Tenant Migration

Regardless of the reason for Migration, specific steps need to be followed when conducting Microsoft 365 Tenant to Tenant migration.

1) Assessment & Planning

Like any other complex project, proper planning is essential in Tenant to tenant migration. It would be best to deeply understand your existing environment, including user account information & your business needs, before beginning this process. A comprehensive assessment helps you identify potential risks & timelines involved.

2) Establish relationship/trust between tenants

Establishing trust between both tenants is required before further action can occur related to migrating identities/user accounts from one Microsoft 365 environment into another.

3) Create new Users/Groups

Now you must create new users/group objects with matching email addresses on your new destination Office 365 environment.

4) Migrate Mailboxes through Office 365 Tenant to Tenant Migration Process

Migrating mailboxes is a crucial step in Office 365 Tenant Migration. You can use third-party migration tools to migrate mailboxes in bulk or manually by using this complete Office 365 Tenant to Tenant Migration guide.

5) DNS Changes

After migrating all users and their data, you must update your domain name system (DNS) records routing email traffic to your new Office 365 tenant.


In conclusion, we hope this article has provided valuable insights into the manual procedure for Office 365 tenant-to-tenant migration. While the process can be complex and time-consuming, it is essential for businesses undergoing mergers or acquisitions. The step-by-step guide outlined in this article should serve as a helpful roadmap for IT professionals looking to migrate their data with minimal disruption to their day-to-day operations. Remember, it is important to stay organized throughout your migration journey and seek help from professionals if needed. If you want to learn more about how you can make your next migration project successful, feel free to contact CloudBik.

Read more: MBOX to PST Conversion

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