Cliff. Many thanks again for your prompt reply. FYI here is a list of acceptable audio formats for the 2025 Audi A5. The 2025 Audi A5's MMI infotainment system supports a wide variety of standard and high-fidelity audio formats. Whether you are streaming or playing locally stored music, the accepted formats include: [1, 2, 3] Lossless/High-Resolution: FLAC Compressed/Standard: MP3, AAC, and M4A Apple: Apple AAC and M4A Others: WMA [1, 2, 3] If you are loading music onto a USB-C flash drive or SD card to use directly with the vehicle's system, ensure that the drive is formatted to FAT32 or exFAT for the best compatibility. [1, 2, 3] I’m using music with the M4A format so it shoukd be ok. I can’t think of anything else to try.