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 available when all domain controllers in a domain or forest are running Windows Server 2008 R2.
For the new domain-wide features to be enabled, all domain controllers in the domain must be running Windows Server 2008 R2, and the domain functional level must be raised to Windows Server 2008 R2.
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
 | 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:
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To raise the domain functional level to Windows Server 2008, click Windows Server 2008, and then click Raise.
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To raise the domain functional level to Windows Server 2008 R2, click Windows Server 2008 R2, and then click Raise.
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To raise the domain functional level to Windows Server 2008, click Windows Server 2008, and then click Raise.
 | Caution |
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Do not raise the domain functional level to a later version (such as Windows Server 2008 or Windows Server 2008 R2) if you have or will have any domain controllers running earlier versions of Windows Server. |
 | Important |
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After you set the domain functional level to a certain value, you cannot roll back or lower the domain functional level, with one exception: when you raise the domain functional level to Windows Server 2008 R2 and if the forest functional level is Windows Server 2008 or lower, you have the option of rolling the domain functional level back to Windows Server 2008. You can lower the domain functional level only from Windows Server 2008 R2 to Windows Server 2008. If the domain functional level is set to Windows Server 2008 R2, it cannot be rolled back, for example, to Windows Server 2003. |
Additional considerations
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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.
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The current domain functional level is displayed under Current domain functional level in the Raise domain functional level dialog box.
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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.
- 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 Domain Functional Level (
https://go.microsoft.com/fwlink/?LinkId=137825 ). For more information about Windows PowerShell, see Windows PowerShell (https://go.microsoft.com/fwlink/?LinkID=102372 ).