Ok, I have the newest version of USB Loader GX. It's recognizing my HDD (fat32), including the storage space, however, it isn't showing any of the games I put on. I use OSX and used Wiijmanager to put the files on. Is it possible they are in the wrong location on the HDD? Do I need USB Loader GX Directly on my USB or is launching from the SD ok?
Launching from SD is just fine. Just go to custom paths in the settings and make sure it's actually looking at USB for games and not SD ... better yet, there's a setting that's something like "all partitions" (I think it's in hard drive settings or something) that you could turn on and I think it will show everything no matter what drive it's on.
Also, I'd assume Wiijmanager would save it in the right place, but just in case, it should have put them in the /WBFS/ folder (probably each in separate folders inside that folder, actually.)