Having same problem

The game crashes when a Steam shortcut is used to run on Mac

O.K., I found the issue, and it's actually something dumb. I was trying to run the game through a Steam shortcut, and that causing the crash, I'll submit a bug report.

Was Skype working after the modem reboot? If not, then it's her internet, if everything else works on her end, then it would be Factorio failing.

So, I just purchased this game, and I went to run it, and after it asked me if I wished to run it(because it was a downloaded application), it threw the Mac error report box. This was a clean install on OS 10.11.1. If you want to see the error, just ask.