How to raise the forest and domain functional level for Windows Server 2003

When doing certain tasks (like adding a Windows Server 2008 R2 domain controller to a Windows 2003 domain) or installing certain applications, you may find that you need to raise the forest and/or domain functional level.

Follow the steps below:

  1. First, we’ll raise the domain functional level.
  2. Open Active Directory Domains and Trusts.
  3. Right-click the domain and select Raise Domain Functional Level…:
  4. Select Windows Server 2003 from the drop-down box, then click Raise:
  5. Click OK when this warning message appears:
  6. This success message should now appear:
  7. Now let’s raise the forest functional level.
  8. Staying in the Active Directory Domains and Trusts control panel, right-click the Active Directory Domains and Trusts root, and click Raise Forest Functional Level...:
  9. The current forest functional level should show as Windows 2000, and Windows Server 2003 will be the only option in the drop-down menu:
  10. Click OK when this warning message appears:
  11. This success message should now appear:
  12. Both the forest and domain functional level are now at their highest level…job done!