I'm using Mac OS 10.7 to load MP3 songs onto a 16GB USB thumb drive (TD). I used the TD right out of the package and loaded 400 songs using the Mac. All appeared to load but only about 200 played in the car and all showed up in one folder - I didn't even expect a folder, but that was fine. I assumed a bunch didn't play b/c they were not all MP3 format, so I converted them. They are all DRM-free. I then loaded all 400 on the TD and 254 showed in one folder and 11 in a second folder - go figure, I didn't use any folders. I'm thinking my next attempt is to 1) erase and re-format the TD and then 2) load the songs into, say 4 folders of 100 songs each. My Mac allows me to format in either MS-DOS (FAT) or ExFAT (assuming I have to format in PC/non-Mac format). Which should I use? Any help available? The Toyota service department can't really help with computer-related issues...