How to debug application_start global.asax in ASP.net

A simple way to break in Application_Start() is to use the System.Diagnostics.Debugger class. You can force the application to break by inserting System.Diagnostics.Debugger.Break() where you would like the debugger to break.

  
    void Application_Start(object sender, EventArgs e) 
    {
          System.Diagnostics.Debugger.Break();
    }
    

Or else

1. Attach the debugger to the IIS process.
2. Open the global.asax file and put in a break point.
3. Add a space to the web.config file and save the file (this causes the current web application to reset);
4. Refresh / goto a web page on the site.
5. Boom debugger stops at your break-point. :)