The view 'name' or its master was not found or no view engine supports the searched locations - asp.net-mvc-5

Question

I'm getting this error message, and any of the advice that I've seen does not appear to be applicable; i.e. all views, controllers and models are in the correct folders.
More detail:
I have a master view, which shows a graphical flowchart-like interface for interacting with the application. The user selects the "Open Study" symbol, and I redirect to another view which allows the user to select a Study to work with.
The OpenStudyController code retrieves the selected study and then redirects back to the master view:
public ActionResult SelectStudy( Guid? id )
{
// code elided for clarity
return RedirectToAction( "ActivateStudy", "Home" );
}
HomeController has a method called ActivateStudy(...), which does get invoked with the appropriate environment:
public ActionResult ActivateStudy()
{
// code elided for clarity
return View();
}
As I said, all views, controllers and models are in the correct folders.
When the "return View()" code in ActivateStudy() is executed, the error message occurs:
Server Error in '/' Application.
The view 'ActivateStudy' or its master was not found or no view engine supports the searched locations.The following locations were searched:
~/Views/Home/ActivateStudy.aspx
~/Views/Home/ActivateStudy.ascx
~/Views/Shared/ActivateStudy.aspx
~/Views/Shared/ActivateStudy.ascx
~/Views/Home/ActivateStudy.cshtml
~/Views/Home/ActivateStudy.vbhtml
~/Views/Shared/ActivateStudy.cshtml
~/Views/Shared/ActivateStudy.vbhtml
What am I missing? Some additional parameter in RedirectToAction(...)? Some new entry in RouteConfig?

Answer 1

If you have a _ViewStart.cshtml and it contains something like the following you do not need to specify the same layout in each view.
#{
Layout = "~/Views/Shared/_Layout.cshtml";
}
I believe your problem might be related to a missing slash. In your comment you said that your view contained the following line:
Layout = "~Views/Shared/_Layout.cshtml"
I think that needs to have a slash after the tilde.
Layout = "~/Views/Shared/_Layout.cshtml"
But, as I said, you should be able to remove that line entirely.

Answer 2

Well, I don't know if this is the "right" way to do it, but, in my HomeController.ActivateStudy() method, I return the Home "index" view:
public ActionResult ActivateStudy()
{
// code elided for clarity
return View( "Index" );
}
And this works.
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