Why wouldn't a umap file show up in the Editor?

I’m teaching an online Introduction to Unreal 4 class and as part of the class the students have to submit their .umap files for me to review. All of the map files have worked fine, with the exception of submissions from a single student. I created a new project of the same version being used by the student, dropped the .umap file into the maps folder of the starter content folder and when I load the editor it simply doesn’t show up. Everyone else’s file shows up and loads fine. Some of the students have said that they’ve been able to load his level but I can’t even get the file to show up for me to attempt to load.

Any idea what might be happening?

I’m having the same problem, an older backup does work. But the most recent one won’t show up. 10 hours gone :confused: