I was given a Windows 7 machine. It has VS2010 and VS2013. It also has .NET 4.5.1 installed.
My web project uses a local IIS and it fails to start in debug when the application pool uses Classic with .NET 4.0. It debugs in Integrated mode.
I followed an article online (probably from stackoverflow)
“open IIS7 (run > inetmgr) and go to the Feature view. Open the ISAPI and CGI Restrictions section and check if your .Net version has the correct restriction (for example, if you’re working with 4.0 is should be on “Allowed”)”