Raise the Domain Functional Level
Applies To: Windows Server 2008
When you install Active Directory Domain Services (AD DS) on a server running Windows Server 2008, 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 available when all domain controllers in a domain or forest are running Windows Server 2008.
For the new domain-wide features to be enabled, all domain controllers in the domain must be running Windows Server 2008, and the domain functional level must be raised to Windows Server 2008.
Membership in Domain Admins or Enterprise Admins, or equivalent, is the minimum required to complete this procedure. Review details about using the appropriate accounts and group memberships at Local and Domain Default Groups (https://go.microsoft.com/fwlink/?LinkId=83477).
To raise the domain functional level
Open Active Directory Domains and Trusts. To open Active Directory Domains and Trusts, click Start, click Administrative Tools, and then click Active Directory Domains and Trusts.
In the console tree, right-click the domain for which you want to raise functional level, and then click Raise Domain Functional Level.
In Select an available domain functional level, do one of the following:
To raise the domain functional level to Windows Server 2003, click Windows Server 2003, and then click Raise.
To raise the domain functional level to Windows Server 2008, click Windows Server 2008, and then click Raise.
Warning
Do not raise the domain functional level to a later version (such as Windows Server 2003 or Windows Server 2008) if you have or will have any domain controllers running earlier versions of Windows Server. After the domain functional level is raised, it cannot be lowered to its previous functional level.
Additional considerations
You can also raise the domain functional level by right-clicking a domain in the Active Directory Users and Computers snap-in, and then clicking Raise Domain Functional Level.
The current domain functional level is displayed under Current domain functional level in the Raise domain functional level dialog box.
To perform this procedure, you must be a member of the Domain Admins group or Enterprise Admins group in AD DS, or you must have been delegated the appropriate authority. As a security best practice, consider using Run as to perform this procedure. For more information, search for "using run as" in Help and Support.
If you are not able to raise the domain functional level, you can click Save As in the Raise Domain Functional Level dialog box to save a log file that specifies which domain controllers in the domain still need to be upgraded to a later version.