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

I got the same error after upgrading the IIS server to .NET 4.5.1 (previously .NET 4.0 was installed). In my case, running aspnet_regiis with the parameter -iru fixed the problem, ie.

C:\Windows\Microsoft.NET\Framework\v4.0.30319\aspnet_regiis -iru

Note: on a 64bit system you should use

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis -iru

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Notes:

• .NET 4.0 and higher (e.g. 4.5.1) all installs into v.4.0.30319, this has changed compared to earlier versions (you will not find a v4.5 folder). To get the installed .NET framework versions, see this answer.

• The cause of this error is described here, If you want to check manually, I cite the following from this article:

This issue occurs because the Applicationhost.config file for Windows Process Activation Service (WAS) has the following section defined, and this section is incompatible with the .NET Framework 4.0:

This section should be defined as follows (notice the preCondition):

Note: You can find the Applicationhost.config file in the following location: %windir%\system32\inetsrv\config