Ctholin

I'd love to solve this, but in an effort not to waste anyone's time any further, I should say that I gave up and grabbed a .78 full set standalone and this is working completely fine for me. Thanks for the help non the less

Are there any settings in RA itself that have an impact on launching externally?

Yes, everything is pointing to RA now. Also, i have still yet to generate a log file using the instructions above.

Another observation If i select Play from the popup menu i see a little window open and close almost instantly (almost like a cmd window?). If I choose Open With -> RetroArch -> mame_libretro, the RetroArch UI widget launches before crashing. By comparison, when i run straight through RA this same RA UI appears, disappears, and reappears as its loading the game, which eventually works. Derp: The crossed out section was a result of me putting command line params in the specific ROM itself. Removing those makes the behavior match the un-crossed out text.

I assume you mean this, if so, they are set to Arcade. Nothing is set to Arcade 2, i was just seeing if that was a good methond for some Arcade roms to launch with a different core All my tests are running with mame_libretro.dll when using RA

I actually removed the standalone mame from LB to both simplify and because everything i need runs in RA so i will solve 1 thing at a time. I tried the log but so far it hasnt actually produced one. Going to keep trying.

@Lordmonkus I believe it wasn't there because the very first thing i did was import a "full mame set" which i regretted and tried to undo. I've gone ahead and added it to the bottom of the list which will overwrite the default status of the standalone mame but i guess i can spot point to that one when needed. (Putting this herein case it helps others. Testing your suggestions now). Update: I made the changes you suggested and tried to run the ROM. It was different, but still didnt run successfully. This time it launched RetroArch UI/shell, i got some spinning loading icons on my mouse pointer, and then it just closed RA and i was back at the LB UI. Similarly, the standalone exe failed as well. As a test, i went into RA itself and launched the ROM and it WORKED. It didnt crap out of the RA UI. Is there anything else i can provide?

Another screen of my RetroArch settings - Associated Platforms. How come there is no Arcade listed here?

Hi everyone I've searched the forums and the web but i think i might need some specific LB help - im assuming i have things config'd wrong I am trying to run MAME games both through LB via Retroarch and just pointing directly at the mame.exe to no avail. Nothing happens when i select play, i almost instantly just have normal command of the LB interface again. The romset i am using was in a package with MAME .133u3. The exe for this actually sucks, it only displays like 10 games and gives me their bios info and its often not clear which game im choosing. Thats a side story, however in this case Knights of the Round DOES work through this exe. Similarly - via retroarch directly using latest mame, i can also run this rom fine. However, LB does NOT run this properly either through RA-MAME or the standalone mame exe I'll attach some screens of my setup via the standalone mame 133 exe (edited for clarity)