Could not load type 'System.ServiceModel.Activation.HttpModule'

Question

I am run aspnet_regiis.exe, still I am getting same error:

Could not load type ‘System.ServiceModel.Activation.HttpModule’ from assembly ‘System.Ser

Answer 1

On Windows 2012, the following worked :

For a reason I don't know the default application pool was set up to use 4.0 :

Application Pool Properties

but it was not correctly reflected in c:\windows\system32\inetesrv\config\applicationhost.config :

I had to set it back to 2.0 and then to 4.0 again, and then the config file was fine and the error disapeared :