Okay, I searched for Shadowplay in the forums, and all it finds is references to a mission in the Derelict mod. I'm guessing this question hasn't been asked yet.
I think I've answered it on my own, but I wanted to mention it in case anyone else ever wonders why Shadowplay won't start recording while playing FS2 Open, despite working in other games, including retail FS2 (which is why I thought posting this in the support forum was appropriate).
Shadowplay currently supports only DirectX, and not OpenGL. So, if you run FS2 Open in OpenGL, you're out of luck as far as Shadowplay is concerned. You'll need to record with something else that does support OpenGL.
That said, anyone have any recommendations for alternatives? I tried Bandicam, since it also supports encoding video on the fly with the GPU, but the software limits your recording time and watermarks your recordings unless you pay. No thanks.
Alternately, is there a way to get FS2 Open to run in DirectX? I know OpenGL is superior, but it'd be nice for the sake of making a video, at least. I'm using 3.7 Final and I don't even see an option to switch to DX, either in Launcher 5.5g or wxLauncher 0.9.4b. Do I need to run a different FS2 Open version or launcher version? (Or both?)
Thanks in advance!