Have you tried the long Format (untick the quick format box) on a PC or laptop? make sure you have it set to Format as FAT32
Thanks Justin - yes! The very long, very slow (overnight even!) maximum security FAT32 format setting on my Mac Studio was the ONLY way I got the sticky USB stick to work with the Kemper Profiler Player. But it only worked on that one stick, not 7 other USB sticks I've tried - including brand new ones. This has got to be a bug surely?