How to Migrate Domain Mailboxes Between Office 365 Tenants ?

admin | February 15th, 2019 | How to, Office 365

Often large organizations procure different small organizations to enhance their turnover and expand into new markets. Just like this, there come times when an organization sells off the small companies acquired by it or breaks down into two small parts. Whether it is a re-branding or divestiture, merger or acquisition, both Office 365 organization’s IT infrastructure needs to be combined with the parent organization. Let’s take an example to understand all this in a more simpler way.

Try to picture this scenario in your mind…Where Company Need to Transfer Domain From One Office 365 Tenant to Another

There are two different companies named ABC, XYZ and both are using Office 365 services. Lately, ABC has acquired XYZ but, both companies are using their own domain names and Active Directory Forests. Other details of both organizations are the following:

ABC (The Parent Company with 390 Users)

  • Domain Name:
  • Active Directory Forest: synced to Azure Active Directory that is using Azure Active Directory Connect Server
  • Uses Hybrid Exchange Online Setup
  • Office 365 Tenant: abc
  • Tenant Address:
  • Uses primary email address as and userprincipalname

XYZ (The Child Company with 121 Users)

  • Domain Name:
  • Active Directory Forest:
  • Active Directory Domain: used to user login and access local resources
  • User Object used to provision mailboxes in O365 tenant

Now, XYZ users are facing issues as their Office 365 userprincipalname is yet, the primary address is This is burdening users as they have to manage two different object passwords for Active Directory domain. So, ABC has purchased a new tenant and now it needs to move all user mailboxes of to this new domain. How this can be done?

How to Migrate Office 365 from One Domain to Another?

In this section, we will demonstrate the means that can be utilized to perform migrate domain between Office 365 tenants.

Important Considerations

Before using the given utility you need to consider some important things:

  1. Target Office 365 account must have O365 license assigned and you must have the capability to access Outlook Web App for the Target account
  2. Make sure you have logged in as administrator on the system in which you are going to run the tool

Office 365 to Office 365 Migration tool is a prominent and automatic solution to transfer or move domain from one Office 365 tenant to another. It allows users to migrate entire user mailboxes from one Office 365 domain to another tenant even without losing a single bit of data. The software migrates emails, contacts, calendars, and tasks of the Office 365 domain. It provides Import CSV option to add O365 source and destination mailbox information. It supports Windows 10 and all below versions to migrate Office 365 domain to new tenant. Follow the instructions below to execute domain mailbox migration:

  1. Launch the Software to Transfer Domain From One Office 365 Tenant to Another. Then choose the radio button next to Without Impersonation
  2. Click on Import CSV button and import the CSV file that contains user account credentials
  3. After adding the CSV, the tool will display account info in its pane and after verifying this, hit the Next button
  4. In the next window, select all the specific data items such as emails, calendars, tasks, and contacts that you need to migrate Office 365 domain to another tenant.
  5. In order to migrate the data of a specific time period, you can use its Date Filter option and click Apply
  6. Now, if you want to map some particular folders then, click on Folder Mapping tab. Here, you can mention the name of different folders you want to map and then, the data will be migrated.
  7. Also, you can provide a folder list whose data needs to be migrated and the data will be moved to the destination user id where a folder exists with the same name
  8. After all this, the tool will redirect you back to the previous window. Now, hit the Export button
  9. Now, move Office 365 domain to another tenant process will begin right after this and the current status of process will be displayed by the software along with Source ID, Target ID, Data Item Counts etc.

It will take a few minutes to transfer domain from one office 365 tenant to another, then you can access data in a new tenant.