have this bug since a week.
Even after the update.
I gather it's forever stuck on that screen..........
Are you running the application in administrator mode?
I also suggest reinstalling the editor.
FMSE wont load my saved game, it keeps loading forever
It's not a bug, it's a matter of having enough (admin) rights that allows the app to read data from memory.
Open Windows start menu, type fmse, right-click on FMSE20 and select "Run as administrator". Then load game again. It should load it in a couple of seconds.