The Mac version just doesn't work for me...
Viewing post in Yorna: Monster Girl's Secret comments
Mac is very picky about RPG Maker games. If you didn't already, check out this FAQ post. If it doesn't help, there's nothing I can do to help. If you are running anything modern as the operating system, it's officially not supported by the game engine. This is not my judgment, RPG Maker devs directly say this in the game engine manual.