There's nothing in the log that indicate anything out of the normal is happening. It looks like someone just clicked "X" on the game to exit it. That's what I thought too reading the log, but I wasn't exiting the game. The game just randomly closed whenever I connected to a LAN game. Some...

Playing Multiplayer LAN for the first time and it keeps randomly shutting down the game with no error or warning. 0.000 2017-05-13 19:06:25; Factorio 0.15.10 (build 29654, mac, steam) 0.000 Operating system: Mac OS X 10.12.4 0.000 Program arguments: "/Volumes/SAMSUNG/Applications/SteamLibrary/s...

I run the latest version of Factorio on Mac (OSX) and every few hours I get an "Unknown Error" that forces the game to crash. I need to Force Quit out of the application. A restart will allow me to reload the game, but an hour or so later I will get the error again. Log file attached.