Preparing new Additional Domain Controller - Error

  • Last Post 03 August 2016
manasrrp6 posted this 02 August 2016

Dear Sir,



I have a 2003 r2 standard 32bit server as my primary DC and want to install a 2008 r2 standard 64bit server as a Additional Domain Controller with a child domain. When I run dcpromo.exe and follow the steps up to where it wants me to name the new child domain and click next,


I get this error:  To install a domain controller into this Active Directory forest, you must first prepare the forest using "adprep /forestprep". The Adprep utility is available on the Windows Server 2008 R2 installation media in the \support\adprep folder. The thing is, I keep getting this message even though I run "adprep /forestprep", "adprep /domainprep", and "adprep /domainprep /gpprep" on my primary DC.



Please find the attached snap shot and command line error that I face when going to create a new Additional Domain Controller




  OS DNS Service Installed Active Directory Installed IP Address DNS IP
DC Windows Server 2003 Standard Yes Yes
ADC Windows Server 2008 Standard Yes Yes



Error arise on both case on ADC i.e.

1.       Without Joining to DC

2.       With Joining to DC









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g4ugm posted this 02 August 2016

Why do you want a child domain? If it’s a new child domain then it’s the first DC in the new domain, not an additional DC in the root domain. By doing this you will move from a single single point of failure, to two interdependent single points of failure... Dave Wade  


manasrrp6 posted this 02 August 2016





I want to make this ADC to

maintain reduncy for enterprise network. If one will failure than other we will

transfer the load and other services.






kennedyjim posted this 02 August 2016

Then you don’t want a child domain.  You want to add another DC to the existing domain.



tanweerakh posted this 02 August 2016

Hi Manas,
This is fine, however it doesn't required to create a Child Domain. While promoting the ADC on 2008 you select New DC in existing Forest.


manasrrp6 posted this 03 August 2016


What we have to check i.e. pre-requisite check before we transfer

FSMO Role to ADC.







kbatlive posted this 03 August 2016

The issue it seems like you are experiencing is the ADPREP commands didn’t work and didn’t extend the schema (and or didn’t do the domainprep

– but if you did that for 2003, I don’t think you have to do it for 2008 or 2008r2). 


The DCPROMO of the 2008r2 DC is checking to see if that was completed (it checks the partitions for specific values) – and the values don’t exist.


Take a look at the ADPREP requirements (schema master, schema master rights, etc) and maybe take a look at this article:


And as others pointed out, you really do not want a new child domain – you want to add a DC to the existing domain.


Good luck!


P.S.  at a minimum you’ll want two domain controllers that are DNS servers in each domain and assuming this isn’t a small business server domain

controller - which I think limits you to a single DC but that is just from me reading about it not ever having used one




kevinrjames posted this 03 August 2016

Lacking the actual error message from adprep (presumably on the 2003x86 schema master), a shot in the dark, but consider;


Windows Server 2008 R2 includes a 32-bit version and a 64-bit version of Adprep.exe. The 64-bit version runs by default. If you want to run one of the Adprep.exe commands on a 32-bit

computer, use the 32-bit version of Adprep.exe (Adprep32.exe).