Randy MD

Hello All, I recently made a live music recording using my Sony Net MD MZ-NF810. Upon completion of the recording, I pressed the stop button, and observed the "Data Save" message flashing in the display. I did not continue to observe the display for any other messages, and instead placed the unit aside in order to allow time for data to be written to the disc. During recording, I monitored the display a few times, and everything appeared to be functioning normally. I could see the recording time and sound level indicators functioning normally. Also, during recording the unit did not lose power or suffer any type of physical shock. However, to my surprise I later inserted the recorded disc into the same unit for playback, and after several minutes of searching, it returned a "Blank Disc" message. Does this mean that the recording did not actually take place? Does this mean that the recording is actually on the disc but cannot be read? I've tried playing some other recorded discs and they work fine. What should be my next step in finding out if there is a recoverable recording on the disc? If there is a recoverable recording on the disc, how do I access it? This is the first time that I have ever encountered this problem. Any and all insight is greatly appreciated.