I'm also having issues loading and saving JSON files, did a strange loading thing happen to anyone else when they were selection a graphic, going off the graphics into the grey area?
Edit: So to follow the new rules, after trying to make a character I went to the glasses tab and it somehow went off screen to a greyed out box, after that the computer was stuck on loading so I saved the character and restarted MV, but when I restarted it I noticed the JSON wasn't there. So I made the character again and tried saving, same result, no JSON file, so then I tried loading a characer I made before but that had no effect on the generator and nothing loaded, insteed just being the the current edited character.