I encountered an error when I was deploying mvc website which targeted .NET 4.5 to Windows 8 os in IIS 8. It was an exception shown in browser whenever I tried to open a web page. The exception said: "Could not load type ‘System.ServiceModel.Activation.HttpModule’ from assembly 'System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'" Microsoft officially announced the solution ( http://support.microsoft.com/kb/2015129 ) for Windows Server 2008 plus IIS 7.5: manually running “ aspnet_regiis.exe /iru ” for .NET framework 4.x (in C:\Windows\Microsoft.NET\Framework\v4.0.30319 or C:\Windows\Microsoft.NET\Framework64\v4.0.30319 ). However, aspnet_regiis.exe is not allowed to run for IIS 8. I tried manually changing applicationHost.config . I also tried removing and adding features in a good order. But all these solutions did not work. The final solution was to delete the 3.x module and handler from ...