For a while now, I haven't been able to run MD3View or GTKRadiant 1.5 or 1.6.5.
MD3View crashed when I did anything with it. GTKRadiant 1.5 showed a blank, black screen. GTKRadiant 1.6.5 simply crashed upon startup. GTKRadiant 1.4 would probably not work correctly either, but I never tested that. I imagine ModView may also be effected by this but I never tested that either.
Regardless, the fix has to do with GeForce Experience Overlay. This needs to be disabled in your GeForce Experience settings, which is reachable by clicking the gear to the upper right of the window. Doing so solved my problems. No more crashes or black/blank screens. Everything just works.
This is extremely important because it effects a wide variety of software and not just GTKRadiant. Please let me know if this solves it for you as well and spread the word!
Basic Tags: Jedi Outcast Jedi Academy JK2 JK3 JKII JKIII JA JO Jedi Knight
Specific Tags: Windows 10 Windows X Crash Black Screen Blank Screen GTKRadiant Modview MD3View
Credit to Xian55 for figuring out the cause of the problem. https://github.com/TTimo/GtkRadiant/issues/569