I have an Active Directory running on Windows Server 2003 and I just installed Windows Server 2008 and joined the domain. I want to install Exchange Server 2010 on Windows Server 2008 to test it out but I keep getting the message below. I went to the Domain Controller and raised the functional level to Windows Server 2003 and above and restarted the server but no good, the error keeps coming back. What should I do? The forest functional level of the current Active Directory forest is not Windows Server 2003 native or later. To install Exchange Server 2010, the forest functional level must be at least Windows Server 2003 native.