Can't debug application when 'just my code' is disabled

I'm having all kinds of issues debugging an ASP MVC 5 application.  If I run the application with 'just my code' disabled the application throws an exception at startup.   I get:

'System.NullReferenceException' in System.Web.Mvc.dll

With a stack trace of:

   at lambda_method(Closure , LoginViewModel )

The debugger points me to a razor cshtml file that is part of the login process (identity 2).  

NOW, if If I enable Just my code everything works BUT then I get a warning that I am trying to run 'Just my code in a release build' and if I continue anyway with this warning I no longer get exceptions thrown in visual studio.  I just get the error/stack trace info in the web browser.

Both of these issues seemed to come out of nowhere.  Things worked and then didn't.  I went back to a previous commit and the issues remain.

I am stuck where I can't properly debug my application.

Thanks,

Brian