shoefrado

Update for anyone else with multiple monitors having this problem: No need to physically unplug your monitor(s) as long as one of them is DVI/DisplayPort. Just change your primary monitor to the non-HDMI one and launch KSP in windowed mode. Can then drag it over to your primary monitor even if it's HDMI. I use BorderlessGaming to run it in full-screen windowed as well.

The above solution seems to turn off OpenGL mode- I successfully started the game with the correct resolution (1920x1080) but it crashed during loading due to hitting the 3.5gb memory limit. On my computer, at least, it loads fine in OpenGL as long as I'm under 1600x900 resolution.