How to Perform Office 365 Tenant to Tenant Migration Step by Step?

Pre-Planning for Office 365 Tenant to Tenant Migration

Here we are going to explain some preparation, which is required before using any expert tool. All the steps are mentioned below in detail.

Step 1: Prepare Domain

1. The license of a Targeted Office 365 Account is required.
2. Make admin accounts in both source and destination accounts for better migration.
3. Now create user mailboxes, room/resource mailboxes, and distribution groups in the destination account.
4. Combine AD DS stuff using AD DS tools. Connect the old domain to the new domain by hand or with synchronization if necessary.
5. It’s really important to teach end users how to use Microsoft 365 after we move to it.

Step 2: Domain Preparations

1. Now start the verification of the target tenant domain in Office 365.
2. Add the source domain in the destination O365 admin center and make TXT records in DNS.

Important Note: Ensure that the domain is being used by only one group. Otherwise, the confirmation won’t work. Once this is done, it might take about three days for the change to show up.

Step 3: Schedule the Process

1. Create a CSV file and add the user mailboxes that are to be migrated.
2. Enter the lowest value of TTL on the MX record.
3. Turn off directory sync for the original group (from the Microsoft 365 control center) so that any changes in the original group’s AD DS don’t get matched with Microsoft 365. It’ll take at least one day to finish turning this off.

Step 4: Migration 365 Tenant to Tenant Migration Step by Step

This step has 4 phases one by one, and you have to follow all the steps carefully.

Phase 1: Pause Incoming Emails

To start, temporarily block the flow of new emails to your original organization. This can be done by altering the main record governing email delivery or utilizing an external tool. Keep in mind the shortest time required for email record updates, which you identified earlier. This information will help you choose the optimal time for this action.

Phase 2: Prepare the Source Organization

Before transferring your Microsoft Office 365 emails to a new organization, ensure that the primary email address is dissociated from all entities within the original organization.

1. Revert the default email address to the original one you used when you initially set up Microsoft Office 365.
2. Remove all specialized licenses for Lync from the original organization. This can be accomplished through the Lync Admin Portal.
3. Set the original domain as the default email address for distribution lists, rooms, and resources.
4. Eliminate any extra email addresses associated with objects in your organization.
5. Using Windows PowerShell, execute the command “Get-MsolUser -DomainName xyz.com”. This will display a list of entities that still employ the primary email address or are reluctant to be disassociated. Address these instances accordingly.

Phase 3: Preparation of Target Domain

This process involves confirming that the initial group is linked to the new location.

1. Begin by setting up the auto-discover CNAME.
2. If you’re using AD FS, establish a new group in the new location for it.
3. Ensure the new user accounts are active in the new location and provide them with the necessary permissions.
4. Set the original group’s email as the primary one for the new users. Also, share their passwords with them.
5. Once user mailboxes are ready, modify how emails are routed and switch to the new Office 365 email address.
6. Lastly, test the ability to send and receive emails in and out of the new location.

Let’s Start the Migration Process

• When you have 500 users or fewer, move emails, calendars, and contacts one by one to the new mailbox. You can choose a specific time frame for moving emails.
• If you have more than 500 users, use a step-by-step method to move data. Users can move contacts, calendars, and only one week’s worth of emails at a time.

This is the time to choose the right migration method. Users can also decide the types and amounts of the data. You can use special computer commands (PowerShell scripts) to do the moving.

However, it’s a good idea to use special migration tools. These tools give you full control over the move and do it quickly and easily for you.