I don't understand, why would it try to render on a screen it wasn't using in the first place? Perhaps the 970 purges the video memory when there's a screen unplugged? I don't really get it. Also looking at the logs it shows the TV as monitor 0, and the DVI monitor it was running on as monitor 1 ...

Ok I got it, apologies for the delay, it's heavily reproducible on my system from the looks of it, game updated to 0.13.13 for this test

0.001 2016-08-01 11:54:31; Factorio 0.13.13 (build 23721, win64, steam)
0.001 Operating system: Windows 7 Service Pack 1
0.001 Program arguments: "C:\Program ...

Crashlog is saved? I'll edit this post with it when I acquire it. The alternate monitor was an HDMI television, to be specific, the main monitor, which the game was running on was just an ordinary DVI monitor.

This is a bit of an odd one, someone came in, and tripped over my TV cable from my computer, while I was playing factorio, unfortunately I didn't get to get a good look at the error message displayed because something important had come up, but it was something about a GL texture I think, and the ...