Office 365 to Office 365 Migration Guide

We’re going to concentrate on finding a way to switch from one Office 365 to another by using the same domain. Through this write-up, we’ll focus on checking out some best practices to prepare a plan, setup, and some other general migration practices. Cases where you need to move out mailboxes to another tenant, requires proper planning, as there is no linear way for Office 365 to Office 365 migration.  

We are going to talk about the reasons behind Office 365 migration through this guide, along with a take away that helps you prepare to migrate from Office 365 to Office 365.

Why do we need Office 365 to Office 365 migration?  

Users might think that Office 365 to Office 365 migration is a simple task, but actually, there is much complexity while moving towards the migration process. Many entities acquire other companies or merge with them to found another entity resulting in generating newer O365 to Office 365 migration projects.  

Now, users might think that migrating to the same platform should be an unproblematic task, but handling a migration project will be a complex task as similar to if you are migrating your mailboxes, users, domain from hosted system to Office 365.  

Manual Office 365 to Office 365 migration steps  

Generally, Office 365 to Office 365 migration can be performed through a manual method using PowerShell script or by an Office 365 migration tool. Now quickly take a tour of the migration steps of Office 365.  

Preparation and pre-migration activities

Domain preparation:  

  • There is a need to make sure that there will be enough left space in the target tenant Office 365 for allowing successful movement of data from source Office 365. It can call for obtaining additional licenses, as well.  
  • Then make administrator in both source tenant and the target tenant.   
  • It is required to synchronize all objects from the Active Directory Domain Services (AD DS) target tenant using the Azure AD Connect tool and ensure that objects from the source tenant AD DS have to be generated by consolidation in the target tenant AD DS.  

Domain verification:  

  • Now, for the source email domain, begin the domain verification process on the target tenant.  
  • Add source tenant domain and make TXT record in DNS (Domain Name Systems) for verification in target tenant Microsoft O365 admin center.  
  • Make sure that only one tenant is operating the domain; otherwise, the domain verification will fail.  

This process will allow making changes and can take up to 72 hours. However, the final validation will happen in the latter part of the process.  

Migration scheduling:  

  • Initiate the list of user mailboxes for migration and creating. CSV file will act as a mapping file to implement matching of source mailbox to the target mailbox.  
  • Need to note down the lowest value of TTL on the MX record for the primary email domain.  
  • Disable directory sync in source tenant Office 365 admin center.  

Migration phase  

Stop the flow of inbound mail:  

 Stop allowing the flowing of inbound emails to source tenants by changing the primary MX record to an unreachable value. Internet mail servers trying to deliver new incoming mail will queue the mail and re-scheduling the delivery within 24 hours.  

Source tenant preparation:

  • The primary email domain must be deleted from all objects in the source tenant before the domain moved to the target tenant.
  • Through the Lync admin portal, delete all Lync licenses from the source tenant users, which results in the deletion of the Lync Sip address connected to the source tenant.  
  • Change the default email addresses of Office 365 to the initial domain.  
  • Reset the default email addresses to the initial domain of the source tenant on all distribution lists, rooms, and services.  
  • Remove all secondary emails from the user objects of a tenant.  
  • Repossess all objects, which are still using the domain and blocking removal Using Windows PowerShell command.  

Target preparation of tenants:  

Make sure to accomplish the verification of the source domain in the target tenant. Please remember, after removing a domain from the old tenant, you will have to wait one hour.  

  • Need to configure the auto-discover CNAME.  
  • For AD FS configure the new domain in the target tenant of Office 365, if using it.  
  • Start initiating the activation of a mailbox in the target tenant and assign licenses to them.  
  • Using Windows PowerShell, you can fix the source email domain as the primary address (New User).  
  • Change mail routing while user mailboxes are active and point the MX record to the new Office 365 email address.  
  • Conduct validation Test of mail flow in/out of the target tenant.  

Conduct migration:  

  • Migration for 500 or fewer users: Migrate to target tenant mailboxes with the Mail Calendar and contact info. If possible, restrict mail migration by date criteria.  
  • Migration for more than 500 users: Approach a multi-pass method to migrate addresses, calendars, and email for one week as it takes time. As the migration of the remaining data takes place in the background; the users can start operating on the target tenant domain.  

These are the Office 365 migration steps that focus mainly on following the conventional approach however, it depends on you whether to go Office 365 to Office 365 migration through Power Shall scripts or to choose a third-party office 365 migration tool.   

Quick approach for Office 365 migration: Shoviv Office 365 Migration tool  

The perfect and quickest way to handle Office 365 to Office 365 migration can be through the Shoviv Office migration tool. It works wonders in moving out source mailboxes to the target tenant. This tool comes with various advanced features that are listed below:  

Add multiple mailboxes  

This tool allows users to add multiple source mailboxes without having a limitation for Office 365 to Office 365 migration.  

Filter added source items  

The function to add or delete added source mailbox items is useful when migrating from a source tenant to another and based on filtering items according to message class and item date criteria.

Preview added mailboxes  

This function allows you to preview the added source mailbox folder items before heading to the final phase of the Office 365 to Office 365 migration.  

Free trial version  

This tool comes with a free demo version to test the functioning of the instrument. Users will be able to process the first 50 items per folder in the demo version.  


The manual method of carrying out Office 365 to Office 365 migration is a complex task, as users need to use Power Scripts and requires users to be technically sound. For easing out the task of moving source mailboxes items to others, it is better to use the Shoviv Office 365 migration tool.

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