Tested guide for upgrade 2003 domain to 2012

1. Raise domain/forest functional level to 2003
   • Domain is raised from AD users and computers
   • Forest is raised from AD Domains and Trusts
2. Prepare AD for 2012
   1. The command adprep is located on your Server 2012 disk under the \support\adprep
      • Run in cmd adprep /forestprep
      • If KB919151 is not installed adprep /forestprep will fail with “ADPREP.EXE is valid, but is for a machine type other than the current machine” – REMARK addprep.exe must be copied from x86(or x64) folder to the folder where all other files (sch1, sch2, and so on, schema.ini is also inside), then run it from there.
3. Install 2012R2 server, join it to the domain and promote it as DC
   • First add active directory feature
     • open elevated powershell

ADD-WindowsFeature AD-Domain-Services

then run

Install-ADDSDomainController -CreateDnsDelegation:$false -DatabasePath ‘C:\Windows\NTDS’ -DomainName domainname.net’ -InstallDns:$true -LogPath ‘C:\Windows\NTDS’ -NoGlobalCatalog:$false -SiteName ‘Default-First-Site-Name’ -SysvolPath ‘C:\Windows\SYSVOL’ -NoRebootOnCompletion:$true -Force:$true

4. Open AD Users and Computers –> right-click on the domain name, select operation masters and change what is needed (PDC, RID, Infrastructure), confirm when asked.
   1. To find where FSMO roles are you can use netdom
      • Netdom query FSMO
   2. Change Domain Naming Master
      • Open AD Domains and Trusts
      • Right click your domain and select Change Active Directory Domain Controller… in the sub menu.
      • In the Change Directory Server window, select This Domain Controller
      • Select your new 2012 R2 Windows Server.
      • Click OK to continue.
      • Back in the Active Directory Domains and Trusts window, hover over the Active Directory Domains and Trusts found in the folder tree on the left hand side to ensure the server now reflects your new 2012 R2 Windows server.
      • Right click Active Directory Domains and Trusts found in the folder tree and select Operations Manager… in the sub menu.
      • In the Operations Master window, click Change to transfer the domain naming master role to the 2012 R2 Windows Server.
      • When asked if you are sure you wish to transfer the operations master role to a different computer, click Yes.
      • Once the operations master is successfully transferred, click OK to continue.
      • Click Close to close the Operations Master window.
      • Close the Active Directory Domains and Trusts console.
   3. To Change schema master
      1. Open an elevated command prompt
         • On the command prompt window, enter regsvr32 schmmgmt.dll and hit enter.
      2. Open a MMC console on your new Windows Server 2012 R2 computer.
         • Click File > Add/Remove Snap-in à elect Active Directory Schema and click the Add button.
         • In the same MMC console, right click Active Directory Schema and select Change Active Directory Domain Controller… in the sub menu.
         • In the Change Directory Server window, select This Domain Controller or AD LDS instance.
         • Select your new 2012 R2 Windows Server
         • Click OK to continue.
         • A warning will appear stating that the Active Directory Schema snap-in in not connected. Click OK to continue.
         • Hover over the Active Directory Schema folder in the folder tree to ensure the new Windows Server 2012 R2 computer is shown.
         • Now right click Active Directory Schema and select Operations Master… in the sub menu.In the Change Schema Master window, click Change to transfer the schema master role to the 2012 R2 Windows Server.
         • When asked if you are sure you wish to transfer the schema master role to a different computer, click Yes.
         • Once the schema master is successfully transferred, click OK to continue.
         • Click Close to close the Change Schema Master window.

7. Once completed, open the Active Directory Users and Computers console to verify that the Active Directory database successfully replicated to your new Windows Server 2012 R2 computer.  Be aware that the database replication may take some time depending on the number of objects in Active Directory.
8. Remove Global Catalog from 2003 server
   • Open AD Sites and Services and Expand Sites –> Site Name –> Servers –> 2003 Server
   • Right-click on the NTDS properties and unselect Global Catalog
9. Triple check FSMO roles transfer – netdom query FSMO
10. Demote Server 2003 à run dcpromo and follow the wizard
11. Once all 2003 domain controllers are demoted you can raise the domain functional level
    • Remark – DO NOT RAISE the level above the level of your oldest version dc, if you have server 2008 DC, the domain cannot be raised higher than 2008

Partially based on this article and other Technet articles.