Get following exception during first load of ASP.NET MVC 4 site in IIS7.5 under Window 2008 R2:

Could not load type ‘System.ServiceModel.Activation.HttpModule’ from assembly ‘System.ServiceModel, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089′.

Easy to fix using following command (run as administrator):
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -iru

Done

P.S. if for some strange reason you still use 32 bit Windows, you should update framework path in command above.

You just setup new Windows 2008 R2 Server, enable IIS role, install ASP.NET MVC 1/2/3 or 4, upload your site, configure IIS (i.e. IIS pool, rights, certificates etc) and get following error in browser:

HTTP Error 403.14 – Forbidden
The Web server is configured to not list the contents of this directory.

Hm… EASY to fix with following command (run command prompt as administrator!):
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

Done

P.S. if for some strange reason you still use 32 bit Windows, you should update framework path in command above.