MonsterTweaks

This happened to me as well. LaunchBox is looking for a core file named snes9x_next_libretro.dll found in c:\EMULATORS\RetroArch\cores. However, the none of the dll core files that RetroArch downloads has the name snes9x_next_libretro.dll. THE FIX: rename the "snes9x_libretro.dll" core file to "snes9x_next_libretro.dll" and LaunchBox was able to emulate Super Nintendo fine after. You can rename any one of those snes9xXXX.dll files and it would probably work as well. I hope this helps someone else.