Hello- When I bought my Tesla few years back, I converted all my iTunes songs to .m4a, which was the recommendation at the time if I remember correctly. I put the .m4a files on a USB stick, insert the USB stick into the Tesla USB receptacle, and all is reasonably well. However, there are about 10 .m4a songs on my USB stick that the Tesla simply won't play. Some are older .m4a files from a few years back, and some I have downloaded from iTunes relatively recently. I get "loading error" or similar when the Tesla player gets to that song. I tried a different USB stick and rewriting the songs to the stick, to no avail. Any other ideas on how I might be able to fix these 10 songs, and whatever songs I get in the future that might not work? Thanks.