I’m sure this will be a noob question but i have to … i installed retroarch and all the other things like cores and shaders (i mean every single download has been made) … and i pointed out my main rom folders for mame … which is rom set 0.172 with all bios and everything … and i tried some games works like mortal kombat 2 and 3 … but some games just getting stuck on loading screen like ultimate mortal kombat 3 and tekken 3 … i searched a lot and saw something about a mame folder inside retroarch/system … and apparently i have to put bios in it but i dont have that folder … wasnt that suppose to create that folder when i was downloading mame cores or when installing retroarch … i just cant understand everything is set up right and i can play most games but some not loading for some weird reason … (funny thing is mk3 uses same bios with umk3 … i mean why is getting stuck at loading and crashes after) … so what did i do wrong can anyone help this brother out … thnx in advance
Do i have to install the new 0.181 mame to retroarch system folder ? O__o
BIOS normally go to the System/BIOS folder you configured in Settings tab --> Directory, but there’s an exception for MAME and FBA, you must put their BIOS files in the same folder you have the ROMs.
You should use the rom set the MAME core asks, load the core first and you’ll notice there’s a number version in the bottom left corner (MAME 2014 0.159 for example, or MAME 2010 0.139, or MAME 0.181…). Remember newer mame cores asks for devices too (qsound.zip for example)
for unofficial mame/fba romsets, try using use markwkidd’s playlist generator:AHK RetroArch Arcade Playlist and Thumbnail Generatorput bios files inside mame/fba roms folder.
Ok now i got new question … whats the difference between mame and ume2014 … cause i always used mame and mame2014 for my main cores … but for a reason that i dont know mame and mame2014 not loading ultimate mk3 and tekken3 … but ume2014 CAN … O__o … ume2014 uses some different settings for this kind a roms or something ? i just tried out of curiosity and baamm… it worked … kind a happy but want to know the reason for future referances … btw thnx for quick response guys 
What happened to the left stick menu? I can set mame controller buttons for systems
UME is MAME+MESS. It should work with MAME2014, download the core again.
believe me i downloaded maybe 4 times of all cores from the start … even tried custom cores from some guys … nada … but as said , its working with ume :\ … well if its not broken then i’m ok … but still dont know why a game with same bios (and infect a clone of it, when every other versions in the same folder) can not be played on mame or mame2014 …
Maybe the source is slightly different between the UME and MAME2014 builds, and the umk3 romset was updated in that period. Try finding a 0.181 MAME romset and use the umk3.zip from that.
umk3 (from 0.181 romset) is working here with mame_libretro.dll (0.181).