Did you try deleting Mario Maker's save folder?
Actually, i deleted all the saves from the save folder, and also loadiine.cfg and everything started working again, however, time to time, this issue occurs, i also manage to repro, as soon as i change the layout from icon to grid or viceversa, and save it, after trying to launch a game, the error starts again, with ALL the games.
I'd never factory reset.
Do you only get it with Mario Maker or all games? Does it happen every time you launch Mario Maker or just the once, or sporadically? You may just be missing a game file or something so it thinks it has that error.
This issue occurs with ALL games, but as example, i can be playing x game, and everything working fine, then after trying to launch another game, and if i get that error, im not able to launch ANY game again, no matter how many restarts and force shutdowns i make, i need to delete the saves on the save folder, and the loadiine.cfg file in order to make it work again.
Doesn't Loadiine lack support for online play?
indeed, it doe snot support online play, but i never said it did O:
