MINI

C:/Windows/Microsoft.NET/Framework64/v4.0.30319/

files >> C:/Windows/Microsoft.NET/Framework64/v4.0.30319/csc.exe.config

 <?xml version ="1.0"?>
<configuration>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <supportedRuntime version="v4.0.30319"/>
    </startup>
</configuration>