Sorry, but since RPG Maker MV has dropped support for Mac, I don’t think it will be supported anymore (the Mac version of Hahienden was removed from the store two months ago). According to Reddit, it seems you can create save files if the game is placed inside the Applications folder, so please give that a try (https://www.reddit.com/r/RPGMaker/comments/18f9vf2/problem_saving_in_mac_builds_...).