After few attempts finally i made the emulator works  it took me a while because of the folder where to put the bios  it always choose the folder itself even if i chose the specific folder  i solved by put the bios in every folder also in the roms folder  but i still have a huge problem  i can't select my external storage ( usb or sd card ) from the path selection for my roms  when i try it crash.. no problem with the internal storage but obviously my storage is not enough since the DC games are quite big  please try to solve. NVIDIA SHIELD USER
July 11 2016