When starting the game and performing clipping 39%, I get an Unexpected Error.

0.000 2017-06-24 12:27:24; Factorio 0.15.23 (build 30400, mac, steam)
0.000 Operating system: Mac OS X 10.12.5
0.000 Program arguments: "/Users/xxx/Library/Application Support/Steam/steamapps/common/Factorio/factorio ...