The view or its master was not found or no view engine supports the searched locations

Be careful if your model type is String because the second parameter of View(string, string) is masterName, not model. You may need to call the overload with object(model) as the second paramater:

Not correct :

protected ActionResult ShowMessageResult(string msg)
{
    return View("Message",msg);
}

Correct :

protected ActionResult ShowMessageResult(string msg)
{
    return View("Message",(object)msg);
}

OR (provided by bradlis7):

protected ActionResult ShowMessageResult(string msg)
{
    return View("Message",model:msg);
}

Problem:

Your View cannot be found in default locations.

Explanation:

Views should be in the same folder named as the Controller or in the Shared folder.

Solution:

Either move your View to the MyAccount folder or create a HomeController.

Alternatives:

If you don't want to move your View or create a new Controller you can check at this link.

In Microsoft ASP.net MVC, the routing engine, which is used to parse incoming and outgoing URL Combinations, is designed with the idea of Convention over Configuration. What this means is that if you follow the Convention (rules) that the routing engine uses, you don't have to change the Configuration.

The routing engine for ASP.net MVC does not serve web pages (.cshtml). It provides a way for a URL to be handled by a Class in your code, which can render text/html to the output stream, or parse and serve the .cshtml files in a consistent manner using Convention.

The Convention which is used for routing is to match a Controller to a Class with a name similar to ControllerNameController i.e. controller="MyAccount" means find class named MyAccountController. Next comes the action, which is mapped to a function within the Controller Class, which usually returns an ActionResult. i.e. action="LoginRegister" will look for a function public ActionResult LoginRegister(){} in the controller's class. This function may return a View() which would be by Convention named LoginRegister.cshtml and would be stored in the /Views/MyAccount/ folder.

To summarize, you would have the following code:

/Controllers/MyAccountController.cs:

public class MyAccountController : Controller 
{
    public ActionResult LoginRegister()
    {
        return View();
    }
}

/Views/MyAccount/LoginRegister.cshtml: Your view file.

In your LoginRegister action when returning the view, do below, i know this can be done in mvc 5, im not sure if in mvc 4 also.

 public ActionResult Index()
 {
     return View("~/Views/home/LoginRegister.cshtml");
 }