Office 365 tenant to tenant migration

1. Prepare a complete inventory of items that you want to migrate.
2. Take a complete backup of your mailbox inventories and remove unused and unwanted mailboxes from the source.
3. Determine the size of the mailbox data and number of mailboxes to migrate.
4. Determine if you want to migrate Public folder and Shared mailboxes along with the user mailboxes.
5. Communicate the plan and the changes to your end users.
6. Prepare the domains and required Active Directory services on the target.
7. Create and prepare the mailboxes and Public folders on the target Office 365 server.
8. Assign suitable licenses to the mailboxes.
9. Ensure you have enough network capacity and bandwidth to migrate.
10. Consider the throttling and message size limits on Office 365.
11. Perform a test Office 365 migration before you start the actual migration.
12. Start the migration, verify the endpoint and add DNS records.
13. Create new Outlook profiles and check if you are receiving mails correctly.
14. Remove the permissions and licenses on the source Office 365 tenant.

I. Pre migration activities for O365 tenant to tenant migration

• On the source Office 365
  1. Assign the Organization Management role group in Exchange online to the admin user on both the source and the target. It is an elevated permission that is required to migrate Public folders and In-Place Archive.
  2. Set the impersonation rights for the admin account in Office 365 to migrate mailboxes on behalf of other users in your organization.Verify if the source and target admin account in general has the following management roles assigned:
     1. ApplicationImpersonation
     2. View-Only Configuration
     3. View-Only Recipients
     4. Public Folders
     5. User management administrator/Global administrator
  3. Check if the Global admin account with the management roles has a valid and non-hidden mailbox on the source and target server.
  4. Ensure that you meet the network and bandwidth requirements for the migration. See network and migration planning, performance factors and best practices for Office 365 migration.
  5. Decide the migration path you want to take depending on your source and target environment.

  Current environment and migration requirement	Migration approach	How does the migration take place?
  You want to perform a complete Office 365 migration in a single event and in a limited time frame.	Cutover migration	In this approach, you set up your target Office 365 tenant and migrate everything in a single sitting. Suited for large mailbox migration
  You want to perform the migration in phases	Staged migration	In this approach, you migrate your mailboxes and mail data in stages and transfer the required or the most recent data first followed by the others.
  You have an on-premises Exchange server that coexists with Office 365 cloud	Hybrid migration	In this approach, you migrate from the source Hybrid environment to the target Office 365 cloud.

• On the target Office 365
  1. Prepare your target Office 365 tenant. See tenant roadmap for Microsoft 365.
  2. Assign the Organization Management role group in Exchange online to the admin user. It is an elevated permission that is required to migrate Public folders.
  3. Ensure that you set the impersonation rights on Office 365 for the admin account to migrate mailboxes on behalf of other users in your organization.
  4. Purchase an Office 365 licensing plan specific to your needs. You can also sign up for a 30 day free trial and decide to go with a suitable one later. Compare Office 365 business plans and Compare Office 365 enterprise plans
  5. Before migrating to the target Office 365 tenant, ensure that you create mailboxes for your users in your organization and assign suitable licenses to them.
     •  Add users and assign licenses to Office 365 users
     •  Add several users at the same time to Office 365
     •  Assign Microsoft 365 licenses to user accounts
  6. If you plan to migrate the source Public folders to Public folders on Office 365, ensure that you create and configure the Public folder mailboxes on the target server.

      Create Office 365 Public folder and assign mailbox user

  7. If you plan to migrate In-Place archives from one tenant to another, enable the archive mailbox on both the source and target. See steps to enable online archive in Office 365.
  8. If you have a custom email domain from the source to which you want to receive emails after the migration, you must add and verify the custom domain on Office 365.

      Steps to add a custom domain to Office 365 and steps to add DNS records to connect your domain.

  9. If you are using Active Directory Federation Services, you must configure a new domain on the target tenant for AD FS.
  10. Configure Office 365 to send and receive large messages

       Follow the steps to increase the message size on Office 365 to 150MB.

II. How to perform Office 365 tenant migration?

There are three methods to migrate Office 365 tenant to tenant.

1. Office 365 cutover migration
2. Batch or staged migration
3. Hybrid migration to Office 365

Steps for Office 365 tenant to tenant cutover migration

• Step 1: Download and install EdbMails Office 365 migration software

  • Download EdbMails and install the application on the source computer. You can also perform the migration operation by installing EdbMails on any non-Exchange server computer.

     See a detailed list of EdbMails system requirements for Office 365 migration.

    

  • Launch the application and click 'Login' or 'Start Your Free Trial'.

    

  • Select the migration technique as shown in the screenshot.

    

  Note: If the Standard folders (such as Inbox, Calendar, Contacts) on your source tenant mailboxes are initialized with a different language, follow the details in the link to migrate these folders to the respective system folders on the target (destination) server.

  For Instance: If your source Inbox folder is named 'Boîte de réception', which is in French language and you migrate this folder directly to the destination server, then by default it will not be mapped to the 'Inbox' folder on the target server. In order to map the folder with the french name to the respective folder, change the regional settings on the target server to match that of your source mailbox folder language (in this case, it is French).

   Click here to know the steps to change the language and regional settings on Office 365

• Step 2: Connect to the source Office 365 as Global Administrator

  In the Connect to Office 365 (Source) window, select the authentication method as Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox. Enter the global administrator credentials to authenticate.

   Connect to Office 365 server using secure modern authentication

  

  

  After you authenticate and log in successfully, select one of the methods to load the mailboxes. You can also load and migrate the mailboxes using a CSV file.

• Step 3: Select the mailbox items and then connect to target Office 365
  1. EdbMails displays a list of mailboxes from the source Office 365 tenant.
  2. Select the mailboxes and folders that you want to transfer.
  3. Click 'Migrate to Office 365' to set up the connection with the target server.

  

  Tip: If this is the first time you’re migrating with EdbMails, the migration is a full migration. On subsequent migrations from the same source to the target, the migration is incremental.

• Step 4: Connect to the target server as Global Administrator

  EdbMails supports both modern and classic authentication. Connect to the target tenant by selecting Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox.

   Connect to Office 365 server using secure modern authentication

• Step 5: Map the mailboxes between the source and the target

  The mapping activity in EdbMails can automatically match and map the mailboxes and folders between the source tenant and target. This activity saves time when you’re migrating a large number of mailboxes.

  

• Step 6 : Start the migration from Office 365 tenant to tenant

  Start and monitor the migration after you complete the mailbox mapping. Finally, verify the count of migrated emails, folders and mailbox items with EdbMails text-based log report.

Office 365 tenant to tenant staged migration

The staged migration with EdbMails involves migrating the newest mailbox data to your Office 365 tenant in the first stage and gradually migrating the remaining items in stages or over weeks.

• Step 1: Install EdbMails and connect to the source Office 365 tenant

  Download and install the application and select Office 365 migration. In the connection page, select Auto Registration and connect to the source Office 365.

• Step 2: Select the mailboxes and folders to migrate to target Office 365
  1. After a successful login, EdbMails displays a list of mailboxes and folders.
  2. Select the objects you want to migrate and click 'Migrate to Office 365'
• Step 3: Prepare your mailbox data for Office 365 staged migration

  EdbMails provides the following additional options to help you perform staged Office 365 migration and filter emails based on the Date and other conditions.

  1. Additional Include and Exclude Filter Options and migration settings for mailboxes.
  2. Filter emails by Date: Migrate to Office 365 by applying the Date filter
  3. Filter emails by Size: Exclude emails or attachments larger than a specified size.

  

• Step 4: Connect to target server as a Global Admin user

  EdbMails supports both modern and classic authentication. Connect to the target server by selecting Auto or Manual registration for modern authentication and the connection method as Mailboxes, Public folder or Archive Mailbox.

   Connect to Office 365 server using secure modern authentication

• Step 5: Map the mailboxes and start the staged Office 365 migration

  The mapping activity in EdbMails can automatically match and map the mailboxes and folders between the source and target server. Start and monitor the migration and verify the count of migrated emails, folders and mailbox items with EdbMails text-based log report.

Benefits of EdbMails for Office 365 tenant migration

• Zero downtime and zero data loss O365 migration
• Migrate SharePoint, OneDrive and Microsoft Teams data.
• Advanced folder and filter settings to selectively migrate the data.
• Easy Exchange online migration with no PowerShell scripts and cmdlets
• EdbMails does not modify the source or the target data and preserves the data consistency.
• Support for secure modern authentication for Office 365.
• Direct connection and automatic mailbox mapping between the source and target.
• World-class and free 24x7 support to assist you with the tenant to tenant migration

 Related Links

1. Videos - Office 365 tenant to tenant migration
2. Videos - Office 365 Public folder to Office 365 migration
3. Videos - Office 365 Archive Mailbox to Office 365 migration
4. Videos - Office 365 to Exchange migration
5. Videos - Export Office 365 mailboxes to PST