So, I used whatever that game was to install Ark on my 3.55 Vita. And I copied an ISO over to my Vita. And I launched it and it works perfectly fine. Except I can't save. It tells me there's not enough space on the memory stick and gives me an option to delete save files. But on the delete save files screen, it tells me there's 4306 MB worth of free space. So, there's clearly enough free space to save my game but it still won't let me.