Compilation Error: [No relevant source lines]

This happened to me after repairing / upgrading my VS 2013 Express

I first tried adding "IIS_IUSRS" and "NETWORK SERVICE" with Modify to the following:

C:\Users\[username]\AppData\Local\Temp\Temporary ASP.NET Files
C:\local\path\to\NET_App
C:\Windows\Temp
C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files

Those did not work. But then I removed the optimizeCompilations="true" from the compilation tag under system.web and everything worked great.

<compilation debug="true" targetFramework="4.5.1" batch="false" optimizeCompilations="false" />

First, try setting "Enable 32-bit Applications" to True for your website application pool if you are running on x64 machine.

If first option doesn't help, Grant Full Accesses for NETWORK SERVICE and IIS_IUSRS group on C:\Windows\Temp\ and C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\