Merging of companies best practice?

Hristo Hristov 1 Reputation point

Hello there,

we currently have Active Directory on premise which is synchronizing its objects to a Azure AD with AAD Connect. We
have acquired a new company with its own Azure AD Domain and they do not have a premise AD. What will be the best way to migrate
them to our domain?

Thanks in advance

Microsoft Entra ID
Microsoft Entra ID
A Microsoft Entra identity service that provides identity management and access control capabilities. Replaces Azure Active Directory.
19,848 questions
{count} votes

2 answers

Sort by: Most helpful
  1. Sandeep G-MSFT 15,086 Reputation points Microsoft Employee

    @Hristo Hristov

    Thank you for posting your query in Microsoft Q&A.

    Let's say you have tenant A where users are synced from on-premises to tenant A using AD connect.
    You have newly acquired new company who has users in Tenant B and they do not have any on-premises environment.

    You will have to first verify Tenant B domain in your Tenant A. For this you will have to remove the domain from Azure AD of Tenant B and then you will be able to verify this domain in your Tenant A.

    Post this you will have to create all the users in Tenant A that you had earlier in Tenant B.
    After doing this you can assign licenses to users accordingly as per your requirement.

    If users had mailboxes online previously in tenant B then you can follow below article to migrate mailboxes to Tenant A.

    Let me know if you have any questions.

    Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

  2. Amit Singh 4,851 Reputation points

    Configure company B as an internal relay domain in company A, en configure a send connector for the respective domains pointing to company B endpoints. If you have mail-users post-migration in company B (eg, mailboxes moved from company B to company A), make sure you set targetAddress to a domain uniquely defined in company A(e.g., when rebranding set to company Aaddress). This prevents you from having 2 locations with disjoint populations requiring internal relays for that domain pointing to each other (with bouncing NDRs). Alternatively, introduce a mail routing domain - similar to Office 365 - such as, which is an accepted domain in company A, the internal relay in company B, and set targetAddress in company B to those entries.

    0 comments No comments