audiobook missing

Are you sure you didn’t use WMA lossless? Sandisk players don’t support WMA lossless.Perhaps you should try rippping it again. I suggest that you rip it to 32 kbps mp3 mono. This will save space and give you longer battery life. Battery life is around 25% or so longer for mp3 than wma files, and using a lower bitrate will not only save space on the player, but further increase the battery life.