Consolidating 7 different AD forests to single forest with multiple AD trees

Copper Contributor


My organization is planning to move out from in-house Linux based Email server (Zimbra) to Cloud based Office 365(hosted Exchange). Part of this initiation I need to consolidate 7 different AD forests to a single Forest with multiple AD trees. Our organization has multiple sister companies with their own AD forest with each having single AD domain. Few forests are trusted. We have good connectivity among the sites (companies).

My challenge is to consolidate all seven AD forests to a single Forest and make the domains name routable ( match the email domain to the AD domain name and allow me to Sync to Azure AD tenant).

My plan:

  1. Create a new forest with company Groupname (we have a domain name registered for this)
  2. Create 7 new AD domain trees under this Forest with new names match with their respective email domain names.
  3. Migrate existing AD Users, Groups and Computer Accounts to respective new domains
  4. Use Azure AD connect to Sync all accounts to Azure AD tenant
  5. Migrate all the mail boxes to Office 365 (hosted Exchange)

 I need to validate these steps and need some recommendation on tools that available for migrating users/computers from old AD domain to new AD domain without touching end user computers.

BTW we have total of 600 computers in the organization.


Thanks, in advanced.



20 Replies


Is this not the correct community post this query? 




HI Charles,

Ad Forest is 2008R2,2012R2,2016?

OS Workstation?

You have 2 chance or use ADMT tool or a new Internal Service ADMS.

Hi Fabrizio,

Thanks for you reply. DC's are Windows 2008R2. Workstations are Windows 7 and Windows 10.

What do you mean by 2 chance?

I am planing to use ADMT in each forest to transfer to new single forest in 7 stages.







Ok you can use ADMT 3.2 for WKS 7 and DCs 2008R2

If you have WKS 8,8.1 or 10 is not possible use ADMT but ADMS Services

Best Regards,


When I read about ADMS service, it is for Migrating to Azure AD DS. Can I use it migrate to for in-house AD DS?



Hi Charles, yes you can use internal services (only for FTE)ADMS Services for migrate AD forest 1 (on premises) to AD forest 2 (on premises).
Cheers Fabrizio

Hi Fabrizio,

Thanks for the info.

I was searching the intent to find ADMS internal service. Could not find much. If you can please pass me few links.



best response confirmed by Charles Nanayakkara (Copper Contributor)

I did by mistake mark this as solution. there is nothing in this post.

Hi Charles,

you can use two way i explain these in my first answer...

ADMT (but not support last OS windows 2016, 8,8.1,10...etc..) or ADMS services (but is internal services MS).

Best Regards


Thnaks Fabrizio,

Could you send me few links about ADMS internal services. I could not find any.

@Charles Nanayakkara wrote:

I could not find any.

I linked some info about the service above?




What's wrong using ADMT for recent Windows OS versions? We are using it with success on internal consolidation so far. However for some scenarios (specially lack of human resources)  ADMS seems to be interesting alternative to.

I understand that for getting ADMS one should contact MS?

Hi Andres, it's nothing wrong except the fact that on the admt guide it is written that Windows 8 and later OS are not supported,so if you have issues you cannot contact microsoft ...

Best Regards,



Hi All,

Thank you all for your suggestions. 

Is there anybody used ADMT successfully with Windows 10 and Windows server 2016 ?


Depends what are definitions for "successfull" and what is starting point. In genertal - there is no probleem with ADMT on W10/2016.

Hi Andres,

yes is possible that work I believe this Smiley Happy but I never tried..

But this scenario is not support for Microsoft it does not mean it does not work.

Best Regards,


1 best response

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