When i allwas open zomboid on my mac it just does this

[golden locust]

When i open zomboid on my mac it allwas puts the screen to up and i cant change the screen size that works but i cant get to it can somone help and my mouše isnt choosing what i am really on

[jolly ridge]

Try going to the Home\Zomboid folder and edit the options.ini file with a text editor.
In that file, edit the fullscreen=true line to fullscreen=false
Then try launching the game again.