Bumping this post as I still haven't been able to figure this out, I have replicated this issue on several systems now as well with fresh installations.
I'm having an odd issue someone might be able to help me with. I've recently built a MAME cabinet and everything seems to be working great, except now if I unplug my wireless keyboard Big Box will not launch Retroarch, it just goes from loading to game over. If I plug the keyboard back in it works as intended. The games work with or without the keyboard connected if I launch Retroarch on it's own. Any ideas? Thank you.