Preparing your Active Directory infrastructure for upgrade includes the following tasks. For more information about running Adprep.exe, see Run Adprep commands. If you are preparing for Windows Server 2008 R2 and your existing domain controllers run 32-bit version of Windows Server, use Adprep32.exe in the support/adprep folder of the operating installation disk. By default, Windows Server 2008 R2 runs a 64-bit version of Adprep.exe. If you are preparing for Windows Server 2008, there is only one version of adprep.exe, located in the sources/adprep folder.

• Prepare the forest schema by running adprep /forestprep.
  
  
• Prepare each domain where you want to install a domain controller that runs Windows Server 2008 or Windows Server 2008 R2 by running adprep /domainprep /gpprep.
  
  
• Prepare the forest for read-only domain controllers (RODCs), if you plan to install them, by running adprep /rodcprep.
  
  

Important

Review the list of operations that Adprep.exe performs in Windows Server 2008, and test the schema updates in a lab environment to ensure that they will not conflict with any applications that run in your environment. There should not be any conflicts if your applications use RFC-compliant object and attribute definitions. For a list of specific operations that are performed when you update the Active Directory schema, see Windows Server 2008: Appendix of Changes to Adprep.exe to Support AD DS and Windows Server 2008 R2: Appendix of Changes to Adprep.exe to Support AD DS.