I updated OSX and that did the trick for me as well. I should have tried to isolate the steam question first! But, all set.

I started running into this same issue today. I'm on mac (14.6.1) and the game will bounce in the dock for ~5 minutes and then exit on its own.

I'm launching from Steam, have never installed any mods, and have played *many* hours successfully in the past. I installed space age, put ~2 hours into a ...