The way mine are set up are gdi, raw, and bin files in a folder per game. I also tried to convert to .chd. If I use just Retroarch it will load both single .chd files and .gdi files. As an experiment I have only two games in Launchbox right now. One game points to a .chd file and the other points to a .gdi file, neither work when launched from LB. For reference these games are from the Sega Dreamcast Champion Collection.