Track labels gone missing

I have recently installed Audacity 2.1.0 to run on Windows 7 and am recording tapes currently. After spending a lot of time recording and then labelling the tracks, which are saved as Export>audio as recommended by the manual, I find those labels missing on re-opening the files! This problem is not addressed in the Q&A pages. How do I overcome this? Also, must the start and end times for each track be marked, as there is no guidance on that either?

Normal audio files don’t support embedded graphical labels.

You can either save an Audacity project which will include any label tracks, or use File > Export Labels… to export a text file listing label start and end points, as well as an audio file.

However if you are merely trying to split a recording into separate songs for export, you need to use File > Export Multiple… . I recommend reading this: Audacity Manual.