When you install Active Directory Domain Services (AD DS) on a server running Windows Server 2008 R2, a set of basic Active Directory features is enabled by default. In addition to the basic Active Directory features on individual domain controllers, there are new domain-wide and forest-wide Active Directory features that are available when all domain controllers in a domain or forest are running Windows Server 2008 R2. For more information, see Understanding Domain and Forest Functionality.

To enable new forest-wide features, all domain controllers in the forest must be running Windows Server 2008 R2 and the forest functional level must be raised to Windows Server 2008 R2. You can use the following procedure to raise the forest functional level using Active Directory Administrative Center.

Membership in Domain Admins in the forest root domain or Enterprise Admins in AD DS, or equivalent, is the minimum required to complete this procedure. Review details about using the appropriate accounts and group memberships at http://go.microsoft.com/fwlink/?LinkId=83477.

To raise the forest functional level using Active Directory Administrative Center

  1. To open Active Directory Administrative Center, click Start, click Administrative Tools, and then click Active Directory Administrative Center.

    Note

    Another way to open Active Directory Administrative Center is to click Start, click Run, and then type dsac.exe.

  2. In the navigation pane, right-click the domain that belongs to a forest whose functional level you want to raise, and then click Raise the forest functional level.

  3. In Select an available forest functional level, do one of the following:

    • To raise the forest functional level to Windows Server 2008, click Windows Server 2008, and then click OK.

    • To raise the forest functional level to Windows Server 2008 R2, click Windows Server 2008 R2, and then click OK.

Caution
  • After you set the forest functional level to a certain value, you cannot roll back or lower the forest functional level, with one exception: when you raise the forest functional level to Windows Server 2008 R2 and if Active Directory Recycle Bin is not enabled, you have the option of rolling the forest functional level back to Windows Server 2008. (For more information about the Active Directory Recycle Bin, see What's New in AD DS: Active Directory Recycle Bin (http://go.microsoft.com/fwlink/?LinkId=141392).
  • You can lower the forest functional level only from Windows Server 2008 R2 to Windows Server 2008. If the forest functional level is set to Windows Server 2008 R2, it cannot be rolled back, for example, to Windows Server 2003.

Additional considerations

  • Domains that are set to the domain functional level of Windows Server 2008 will be raised automatically to Windows Server 2008 R2 at the same time that the forest functional level is raised to Windows Server 2008 R2.

  • You can also perform the task in this procedure by using the Active Directory module for Windows PowerShell. To open the Active Directory module, click Start, click Administrative Tools, and then click Active Directory Module for Windows PowerShell. For more information, see Raise the Forest Functional Level (http://go.microsoft.com/fwlink/?LinkId=141939).

    For more information about Windows PowerShell, see Windows PowerShell (http://go.microsoft.com/fwlink/?LinkID=102372).

Additional references

  • Raise the Domain Functional Level
  • Manage the Domain With a Different Domain Controller