Huh, without an preference file idk what to do to fix it.
Have you tried deleting and redownloading the file from the site? If not then try changing your screen resolution to 1280 x 720 as that is what the game is native to. If that does not work then playing here on the site is prob' going to be the only way to play it till next update, or someone who is more knowledgeable about macs and unity player will help.