MP3Tag wants to see your Sansa as a flash drive, it’s the one limitation of the application I see. Well, it isn’t a bad limitation actually, it just means that MP3Tag cannot edit the tags on the device if transfers are made in MTP mode.
Simply edit the tags with the original files on your PC first, then transfer the corrected files to your device as usual. Because of the various file types I personally work with, I use MTP mode for most file transfers. It’s better to edit the files on the computer anyway, as it’s wise to keep a backup on the computer anyway.
Did you download the files from a library source, or were the audiobooks from a CD? If they are from a library source, they may be protected media, meaning that they have to be loaded using MTP mode (for the licenses).
If the books are from CD, and the chapters are converted to MP3 format using a ripping engine like Windows Media Player, the track names can easily end up being messed up. This is because the online database used for the track data is primarily for music , and audiobooks are less common. MP3Tag is your friend when it comes to correctly entering the track (chapter) numbers and titles.
THe first time you use MP3Tag, it can seem difficult, since the application has so many tools available. Once you get the hang of it, audiobooks are easily fixed.
Bob 
