sansa clip+ does not see the audiobooks I loaded

I have had my Sansa Clip+ MP3 player for two years and it has been working very well, until now.  I use it only for audiobooks.  I recently reformatted the player and loaded some new books in.  When I went to play them, the Audiobooks folder was empty.  I attached the player to the computer again, and the books were in the audiobooks folder, where I had loaded them.

I updated the firmware to Version V01.02.16A, and there was no change.  I tried resetting by holding down the start key. No change.

The memory has 3750 Mbytes with 3135 free, indicating that there are books in memory, but the player does not see them.  What’s going on?

And you’re sure that the files are in a format that the Clip supports, right?

Are the ID3 tags of these new books correct (and in ID3v2.3 ISO-8859-1 format)? MP3Tag is a great dedicated tag editor you can use to check and/or modify them with.

That’s it!  I checked the format of the audio files.  It is AAC, with suffix .m4a.

The Sansa manual says:

“The Sansa® MP3 Player will support MP3, WAV, WMA, secure WMA, FLAC, Ogg Vorbis, and audiobook formats.”  I guess AAC is not one of the formats they support.  So I have to convert from .m4a to .mp3.  I guess there are a lot of tools to do that.  Any suggestion as to which one is best?

Thank you very much for this revelation.

Converting to mp3 format is eassier than I thought.  There is an option within Itunes to convert.  Thank you very much for this solution.