I know - another "Launchbox won't load retroarch MAME" question. Sorry. I am reasonably well versed in this stuff at this point and I am stuck. I will address the common follow-ups real quick:
Yes, "extract roms" is unchecked in both the main setting and associated tab.
Yes, Retroarch WILL run any MAME rom I ask it to from within Retroarch itself.
Yes, I know I should "just use MAME", but MAME has the issue of needing controllers setup and frequently confusing which monitor to display on, and I wanted this to be a portable version of Launchbox. Retroarch MAME is super easy in terms of needing little setup.
Launchbox RA-mame will load some roms, oddly. Neo Geo stuff like 3 Count Bout and Sega's Altered Beast work. However MANY, most even, titles won't load. Games Aliens and Alien vs Predator. I am giving examples early in the alphabet because this was an instant test and fail situation. I've played around a lot and can't get launchbox to load. Again, these do guaranteed work and load in Retroarch, so it has to be something in the LB communication. And the fact that a few do work means that it's not a path issue.
Any advice or new things to look at is greatly appreciated.
Thanks guys!