13 Dec 2011 Cannot Install .Net Framework 3.5.1 On Server 2008 – 0×80070643 Written by Allen White. Posted in Exchange 2007, Exchange 2010, General, Microsoft, SBS2008/2011, Server 2008 When installing the .net framework 3.5.1 feature on server 2008 it fals with the error 0×80070643, this can be fixed with this solution