Yamaha PocketrakCX - POCKETRAK CX 2 GB Digital Player Reference Manual page 79

Q: I cannot play a recorded file that was stored on the computer and transferred
back to the unit.
A: You may have changed the file name on the computer. If you change the file name, the file
will not play, even if it is transferred back into the VOICE or LINE folder. However, you will be
able to play the file if you transfer it into the MUSIC folder.
POCKETRAK CX Reference Manual
Appendix
79