I haven't found any direct discussion about this, but I think this user might have had the same issue. http://www.gameex.info/forums/topic/13182-freshly-installed-gameex-cant-find-roms/?hl=%2Bmameui+%2B7z#entry107176 I have some MAME roms, and they are in .7z files. MAMEUI64 sees them fine, and has them as working. GameEx doesn't appear to be listing any of my .7z roms. It did however find the CHD files, and list all those games. Any help to solve this would be appreciated. I could switch back to a non-7z set, but I would prefer not to.