Windows Server 2008 R2 has been upgraded from Windows Server 2008 R2 to Windows Server 2012. You can’t open an ASP.NET website to load an assembly.

Reinstall the system when the data disk is not moved, the website configuration file and even the storage directory and so on are not moved, after the deployment of the problem. I later learned that the MVC 4 component was missing, and when it was installed, everything was fine, but I didn’t even know where the component was used on the site.

Related environment: Windows Server 2012