Debug .NET 4.5.1 Source System.Web.dll with Visual Studio 2013

I'm trying to debug with Visual Studio 2013 and want to go into the .NET source, especially System.Web.dll, but it can't find the correct .pdb file.

I've already gone through the following steps:

• set up visual studio as a setup guide from Microsoft: http://referencesource.microsoft.com/setup.html
• added http://referencesource.microsoft.com/symbols/ as symbol server
• download source and set it as symbol directory

The project is an ASP.NET WebForm project targeting the .NET 4.5.1 platform

In web.config, I set the target framework to 4.5.1 and

<compilation debug="true" targetFramework="4.5.1"/>
<httpRuntime targetFramework="4.5.1" enableVersionHeader="false"/>

      

        
        
        
      

    

My test machine is running Windows 8.1 and I'm using a local IIS server.

When the symbol debug loads but a look in my symbol directory in FailedLoads shows many symbols are not loading.

_WINDOWS_Microsoft.Net_assembly_GAC_64_System.Web_v4.0_4.0.0.0__b03f5f7f11d50a3a_System.Web.txt

with content:

Not found

System.Web.dll is in the list of Assemblies that should have symbols, but when I want to load them, it cannot find them.

How to debug .NET System.Web.dll in visual studio 2013