Automapper - Mapper already initialized error

I've used this method before and it worked till version 6.1.1

 Mapper.Initialize(cfg => cfg.CreateMap<ContactModel, ContactModel>()
            .ConstructUsing(x => new ContactModel(LoggingDelegate))
            .ForMember(x => x.EntityReference, opt => opt.Ignore())
        );

Since version 6.2, this doesn't work any more. To correctly use Automapper create a new Mapper and us this one like this:

 var mapper = new MapperConfiguration(cfg => cfg.CreateMap<ContactModel, ContactModel>()
            .ConstructUsing(x => new ContactModel(LoggingDelegate))
            .ForMember(x => x.EntityReference, opt => opt.Ignore())).CreateMapper();

        var model = mapper.Map<ContactModel>(this);

When you refresh the view you are creating a new instance of the StudentsController -- and therefore reinitializing your Mapper -- resulting in the error message "Mapper already initialized".

From the Getting Started Guide

Where do I configure AutoMapper?

If you're using the static Mapper method, configuration should only happen once per AppDomain. That means the best place to put the configuration code is in application startup, such as the Global.asax file for ASP.NET applications.

One way to set this up is to place all of your mapping configurations into a static method.

App_Start/AutoMapperConfig.cs:

public class AutoMapperConfig
{
    public static void Initialize()
    {
        Mapper.Initialize(cfg =>
        {
            cfg.CreateMap<Student, StudentViewModel>();
            ...
        });
    }
}

Then call this method in the Global.asax.cs

protected void Application_Start()
{
    App_Start.AutoMapperConfig.Initialize();
}

Now you can (re)use it in your controller actions.

public class StudentsController : Controller
{
    public ActionResult Index(int id)
    {
        var query = db.Students.Where(...);

        var students = AutoMapper.Mapper.Map<List<StudentViewModel>>(query.ToList());

        return View(students);
    }
}

If you want/need to stick with the static implementation in a unit testing scenario, note that you can call AutoMapper.Mapper.Reset() before calling initialize. Do note that this should not be used in production code as noted in the documentation.

Source: AutoMapper documentation.