Need to add tenant in the existing domain or merge the tetants

Question

I want to merge the domains of both company domain in to one tenant. Can you walk me through the steps and get it done.

Answer 1

Hello @AGFinTax IT

I understand that you would like to combine two company domains into a single Microsoft 365 tenant.

To confirm the situation and suggest the troubleshooting steps in the right direction, may I confirm a few points: 

• How many Microsoft 365 tenants do you currently have? (1 tenant/ 2 tenants/ More than 2 tenants)
• How many custom domains are involved? Example:
  • Tenant A -> abc.com
  • Tenant B -> def.com
• Which tenant do you want to keep as the final tenant?
• Are both domains expected to remain active after the migration?
• Are the following services being used in either tenant? (Exchange Online (email), OneDrive, SharePoint Online, Microsoft Teams, Microsoft Entra ID)

Besides, to avoid any confusion, I would like to clarify a few points below.

What is possible

• Multiple domains in a single Microsoft 365 tenant are supported. For example, one tenant can contain both abc.com and def.com.
• Moving a domain from one tenant to another is possible, provided the domain is first removed from the source tenant before being added to the destination tenant.
• Tenant-to-tenant migration is supported for workloads such as Exchange Online mailboxes, OneDrive, and SharePoint through Microsoft's cross-tenant migration capabilities.

What is not possible

• A direct "tenant merge" does not exist. Microsoft does not provide a one-click option to combine two Microsoft 365 tenants into one. Tenant consolidation is typically performed through migration activities.
• The same custom domain cannot exist in two tenants at the same time. A domain must be released from the source tenant before it can be verified and added to another tenant.
• Users, mailboxes, Teams, SharePoint sites, groups, and licenses are not automatically combined when consolidating tenants. These items generally need to be migrated and recreated as part of the consolidation process

For your reference:

I have found some Microsoft official article that might be related to your concern:

Add a custom domain to Microsoft 365

Add your custom domain name to your tenant

Cross-tenant mailbox migration

If the issue still remains after trying all the steps above, please share a screenshot or provide more detailed information. I will check the situation and continue to support you. 

Kind regards, 

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