Office 365 Tenant to Tenant migration step by step guide

Planning is essential for a successful migration. A well-thought-out plan saves time and ensures a smooth, stress-free operation. Here's a checklist of crucial points to consider when migrating your O365 mailboxes.

1. Create a comprehensive inventory of items for migration.
2. Back up your mailbox inventories and remove unused or unwanted mailboxes from the source.
3. Determine the size and number of mailboxes to be migrated.
4. Decide whether to migrate Public folders and Shared mailboxes in addition to user mailboxes.
5. Communicate the migration plan and changes to end users.
6. Prepare domains and required Active Directory services on the target.
7. Set up mailboxes and Public folders on the target Office 365 server.
8. Assign appropriate licenses to the mailboxes.
9. Ensure sufficient network capacity and bandwidth for the migration.
10. Consider throttling and message size limits on Office 365.
11. Perform a test migration to Office 365 before proceeding with the actual migration.
12. Initiate the migration, verify the endpoint, and add DNS records.
13. Create new Outlook profiles and ensure proper mail reception.
14. Remove permissions and licenses from the source Office 365 tenant.

1. On the source Office 365
   1. Choose the migration path based on your source and target environments.

      Current environment and migration requirement	Migration approach	How does the migration take place?
      Migrate Office 365 Tenant to Tenant in a single event and in a limited time frame.	Cutover migration	Set up your target Office 365 Tenant and migrate everything in a single sitting. Suited for large mailbox migration
      Perform Exchange online to Office 365 migration in batches	Staged migration	Migrate your mailboxes and mail data in stages and transfer the required or the most recent data first followed by the others.
      Migrate from on-premises Exchange server that coexists with Office 365 cloud	Hybrid migration	Migrate Exchange online to Office 365 while also migrating from the Hybrid Exchange server

   2. Ensure that your network and bandwidth meet the requirements for the migration. See network and migration planning, performance factors and best practices for Microsoft 365 migration.
   3. 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.
   4. 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

      EdbMails automatically sets impersonation rights in Office 365 to the Global admin user.

   5. Ensure that the Global admin account with the management roles has a valid and non-hidden mailbox on both the source and target servers.
2. On the target Office 365
   1. Prepare your target Office 365 Tenant. See Tenant roadmap for Microsoft 365.
   2. Explore various Office 365 licensing plans to find one that best fits your needs. You have the option to start with a 30-day free trial and later select a plan that suits your requirements. Make use of the resources available to compare different Office 365 business and enterprise plans before making a decision. Compare Office 365 business plans and Compare Office 365 enterprise plans.
   3. Before migrating from one Office 365 Tenant to another, make sure to create mailboxes for your organization's users and assign the appropriate 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
   4. If you intend to migrate the source Public folders to Public folders on Office 365, make sure to create and configure the corresponding Public folder mailboxes on the target server
   5. To migrate In-Place archives from one tenant to another, make sure that the archive mailbox is enabled on both the source and target. See steps to enable online archive in Office 365.
   6. 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.
   7. 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.
   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.

The following methods can help you migrate tenant to tenant in Office 365

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

• Steps for tenant to tenant Office 365 cutover migration
  • Step 1: Download and install EdbMails Office 365 migration software

    • Download and install the EdbMails application on your computer. The application is compatible with all Windows server and client operating systems.

       See a detailed list of EdbMails system requirements for o365 to o365 migration.

      

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

      

    • Select the option ‘Office 365 migration’ and proceed

      

    Note: If the standard folders (such as Inbox, Calendar, Contacts) on your source tenant mailboxes are initialized with a different language, For instance, if your source Inbox folder is named 'Boîte de réception' in French language, and you migrate this folder directly to the destination server, it will not be automatically mapped to the 'Inbox' folder on the target server. To ensure proper mapping of the folder with the French name to the respective folder, refer to this link.

  • Step 2: Connect to Office 365 source server

    In the Connect to Office 365 (Source) window, select the authentication method as ‘Auto’ or ‘Manual’ registration for modern authentication and click the ‘Login’ button.

     Connect to Office 365 server using secure modern authentication

    

    Select the required connection method and authenticate on the Microsoft sign-in page using the global admin account.

    

    After the successful authentication, 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 connect to the target server
    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

    Connect to your target server by selecting Auto or Manual registration for modern authentication and the required connection method.

     Connect to Office 365 server using secure modern authentication

    After the successful authentication, select one of the methods to load the target server mailboxes and continue with the mailbox mapping.

     Tip: 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. You can also manually map source folder/subfolders with target folders/subfolders

    

  • Step 5: Start the migration from Office 365 Tenant to Tenant

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

• Steps for Tenant to Tenant O365 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. Connect to your source Office 365 server and select the required method to load the mailboxes.

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

    EdbMails provides the following additional options under ‘Settings’ to help you customize the staged O365 tenant migration and filter emails based on the Date and other conditions

    1. Additional include and exclude filter options
    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.
    4. Filter emails by domain: You can filter the emails for migration based on the Sender Address or email domain.

    

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

    Connect to your target server by selecting Auto or Manual registration for modern authentication and the required connection method.

     Connect to Office 365 server using secure modern authentication

    After the successful authentication, select one of the methods to load the target server mailboxes and continue with the mailbox mapping.

  • 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.

    You can also map source folders/subfolders with target folders/subfolders.Start and monitor the migration and verify the count of migrated emails, folders and mailbox items with EdbMails text-based log report.

• Tenant to Tenant Office 365 Hybrid migration

  If you plan to migrate from a coexisting on-premises Exchange and Office 365 environment to the target Office 365, then a Hybrid migration is the best solution.

   See Office 365 Hybrid migration steps by using EdbMails

  If your mailboxes are in a Hybrid environment, it is not possible to migrate Public folders directly to Office 365. Refer to this workaround solution to migrate Public folders in a hybrid environment.

• Step 1: Update the MX records to point to Office 365

  Add the existing domain to the target Office 365 and if you haven’t updated the DNS records previously, you must change the MX records to enable email flow and receive messages. In addition to this task, configure the Autodiscover record to enable Outlook to connect to the migrated mailboxes.

• Step 2: Clear the Auto-Complete list in Outlook

   See manage suggested recipients with Auto-Complete.

• Step 3: Create a new Outlook profile after Office 365 migration
  • Ensure you have the latest version of Outlook installed to avoid compatibility issues.
  • Configure the Outlook profile for each user in your domain if Outlook has problems connecting to Office 365 mailboxes.
  • Configure the new server settings, such as the server address, username, and password in Outlook.
  • Test email flow to ensure that your users are able to send and receive emails.
• Step 4: Remove the old Office 365 subscription plan

  Once the migration is complete and you have confirmed the integrity of the migrated mailbox data, proceed to remove the Office 365 subscription plan from the source tenant, along with any associated domains.