Do you have an ini file for each system, or just one (ini\mame.ini) ? an ini file for each system When you say it 'disappears', what do you mean? the messui closes, ends. What were you doing exactly when that happened? I tried to play Castlevania and others games on Nes machine with HLSL shaders, just with messui default settings mameui doesn't recognize nes roms, I don't know how run nes roms with mameui...