Step 1: Preparing your existing forest via the adprep command
- Insert the Windows Server 2012 DVD into the DVD drive of the Windows Server 2008 R2 AD DS.
- Open command prompt, and type adprep /forestprep and press enter.
- Check the Schema version of AD DS (After adprep) by running regedit, navigating to Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\NTDS\Parameters and noting the current Schema version.
Step 2: Promoting the Windows Server 2012 Server domain controller in the Exiting Domain
Step 3: Verify the new Windows Server 2012 Domain Controller
- Open Active Directory Users and Computers, expand <Your Domain> and click the Domain Controller OU to verify your server is listed.
- Open DNS Manager, right-click on <Your Domain>, select Properties and then click Name Servers Tab. Verify that your server is listed inName Servers: lists.
- Open Active Directory Sites and Services; verify that your server is listed in Servers under Default-First-Site-Name.
Step 4: Transferring the Flexible Single Master Operations (FSMO) Role
- Open the Active Directory Users and Computers console on your new Windows Server 2012 computer.
- Right click your domain and select Operations Masters in the sub menu.
- In the Operations Masters window, ensure the RID tab is selected.
- Select the Change button.
- Select Yes when asked about transferring the operations master role.
- Once the operations master role has successfully transferred, click OK to continue.
- Ensure the Operations Master box now shows your new 2012 Windows Server.
- Repeat steps 4 to 6 for the PDC and Infrastructure tabs.
- Once completed, click Close to close the Operations Masters window.
- Close the Active Directory Users and Computers window.
Step 5: Removing the Windows 2008 R2 domain controller
- On the Windows 2008 R2 server click Start, Click Run, type dcpromo, then click OK.
- After the Welcome to the Active Directory Installation Wizard page, be sure to leave the Delete the domain because this server is the last domain controller in the domain unchecked.
- On the Administrator Password Page, enter your password and click Next.
- On the Summary page, click Next, wait for the process to end, then click Finish.
- On the Completing the Active Directory Domain Services Installation Wizard, click Finish.
- On the Active Directory Domain Services Installation Wizard page, click Restart Now to Restart the server.
- After the reboot is completed, delete the Windows Server 2008 R2 server from the domain to a workgroup and remove any unnecessary record from Active Directory Sites and Services.