Dunno any details about the MPC4K‘s file system, but 16 chars seems reasonable (iirc 20chars may be entered, but not all visible, depending on disk hierarchy)
If you plan to copy with the M1 Mac, read this first:
https://macpaw.com/how-to/clean-sd-card ... formatting(while about SD cards, the same applies to any drive mounted by a current Mac)
btw ak.sys doesn‘t run well on any OSX Mac, let alone an M1.
Mine is on OS9 and I noticed it occasionally skipped samples when bulk-converting CD Roms.
Not a big deal, but of course annoying if you only find out later. Now I check if source-target match in file count, while the original data is still loaded.
In all other aspects ak.sys is a rather sophisticated and well designed software.
