Office 365 tenant migration: Detailed steps about the process

Office 365 is among the most used online collaboration tools by enterprises worldwide.

This post discusses performing an Office 365 tenant migration, as it can prove helpful during mergers and acquisitions.

Organizations prefer using Office 365 for its straightforwardness and versatile software applications.

However, those aren’t the only aspects that attract millions of users worldwide to this online collaboration suite; it also offers one of the most straightforward tenant-to-tenant migrations.

Organizations undergo Office 365 tenant-to-tenant migration during mergers, acquisitions, divestiture, or rebranding.

Tenant-to-tenant migration involves migrating domains, One Drive accounts, and mailboxes from one tenant to another.

Since no inbuilt option is available for source tenant-to-tenant migration, one must use PowerShell scripts or 3^rd party Office 365 migration tools.

This article details the Office 365 tenant migration procedure. It also discusses migrating One Drive accounts and mailboxes.

Office 365 tenant-to-tenant migration

We can classify the Office 365 Tenant-to-Tenant Migration into two stages, a) the Pre-migration and b) the Migration stage. Both these stages are crucial to the migration process.

The preparatory or the pre-migration stage

This four-step process facilitates the migration process.

Domain preparation

1. The target tenant’s Office 365 should have sufficient space for successfully migrating all data from the source tenant. At times, you might be asked to obtain additional licenses.
2. The source and target tenant should open administrator accounts because some migration tools need administrator accounts.
3. One should create distribution groups, user mailboxes, and resource mailboxes in the target tenant.
4. The process might require performing AD DS (Active Directory Domain Services) consolidation, followed by synchronizing the source and target domain.
5. Finally, train end-users to use Office 365 after the migration.

Domain verification

1. Start the target tenant domain verification process in Office 365.
2. It requires adding the source domain in the target Office 365’s admin center. Besides, one must create TXT records in DNS.

However, the domain should be in use for one target tenant alone. Otherwise, the procedure will fail. The verification process will take around 72 hours.

Migration scheduling

1. The process starts by generating a user mailbox list for migration and then creating a CSV file for mapping.
2. Next, one must note the TTL (Time to Live) lowest value on the MX record of the primary email domain.
3. The final step is disabling the directory sync for the source tenant.   

Migration facilitation

1. Once you note down the lowest TTL value, it becomes easy to change the primary MX record and maintain it at an unreachable level. It stops the inbound email flow to the source tenant.
2. Erase each object from the source tenant’s primary mail domain before transferring the Office 365 mailbox to another account.
3. Finally, verify the source tenant in the target domain. This step should be performed one hour after completing the previous actions.
4. If you use the AD FS, you must configure a new domain for the target tenant.
5. The next step is activating new users in the target domain and assigning new licenses.
6. Ensure that the source domain has the primary email address for the new users. Finally, share the passwords with the new users.   

Thus, you finish the pre-migration process. Now, you can use 3^rd party migration tools or PowerShell scripts to proceed further.

The actual migration stage

Two methods are available for migration, a) for less than 500 members and b) for more than 500 members.

• Less than 500 users – Setting a cut-off date helps limit the volume of migrated data. For example, one can select a specific period, like six months, for migrating calendar data, contact information, and emails.
• More than 500 users – Usually, the IT admin teams adopt a multi-pass approach if the number of users exceeds 500. However, the migration process takes time. So, it is better to migrate calendar data, contact information, and emails for one week. Then, the migration can take place in the background while the users can start functioning on the target domain. 

We have discussed how the Office 365 tenant-to-tenant process works. Now we look at other migration possibilities.

Transfer Office 365 subscription to another tenant

It entails the following steps:

• Purchase an individual plan to where you wish to transfer data.
• The next step is removing the custom domain from your existing Office 365 account.
• Set the custom domain in your new plan.
• Finally, cancel the current plan.

How to merge two Office 365 tenants

Use the Office 365 merger tools for merging two tenants.

• Install the merger tool and log in to the system using the first Office 365 user ID and credentials.
• Add the second user to the account.
• Select the Import CSV option and insert the corresponding CSV file.
• Choose the appropriate location for the CSV file to combine the two Office 365 accounts.
• Choose all IDs requiring a merger. Then, you can apply filters and grant the necessary permissions.
• Import the CSV file and use the data filter option to specify the interval that decides the exported volume data.
• Choose the Export option and merge the accounts.
• You can save the report and view it whenever you want.

Office 365 One Drive tenant-to-tenant migration

This complicated process requires using a migration engine for the smooth transfer process.

• Create a source connector.
• Configure the source and create a target connector.
• Configure the target and create the users before migration.

Transfer Office 365 mailbox to another user account

It can be done through the following steps:

• Recreate the Outlook profile, procure the third-party license and create more admin accounts.
• Add new users you want to be synced with the target tenant.
• Train the users using the Outlook web version.
• Add the domain to the target tenant.
• Prepare the mailbox list for migration.
• Stop the source tenant syncing. Do the TTL test and disable the incoming emails temporarily.
• Verify the source tenant and the mailboxes at the target tenant.
• Depending on the number of users, you use the migration method, as discussed earlier.

Final words

The office 365 tenant migration is not cumbersome if you follow the steps diligently.

Besides following the steps mentioned above, keep yourself updated with Microsoft’s policies and the latest developments for office 365

So if need be, you can implement these updates during the migration process.

Lastly, if you’re unsure about handling the migration process, reaching out to experts who have performed migrations for many organizations and have established a name for themselves is always a prudent choice.

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