Sitecore Experience Editor never stops loading

Question

On my local instance of Sitecore 9 update 2, when I view a page in the Experience Editor, the loading graphic appears and never goes away. The underlying page is visible. However, the Experience Editor's ribbon is not shown.

Has anyone experienced this? How did you correct it?

Answer 1

It happened to me on the vanilla Sitecore site which by default uses the Sample Layout based on ASP.NET Web Forms (i.e .aspx and .ascx files). I meant to use MVC, hence the default layout was incompatible, and as soon as I created a .cshtml file and my MVC layout item in admin, the problem has gone.