"You’re looking at the file names on your computer. Your Fuze+ is looking at (and sorting by) the ID3 tags , not the file names.
Leading zeros (as mentioned) is a must with this many files iin 1 book. but you must add them to the tags."
Can you explain precisely how to modify the ID3 tags using Mp3tag. I’ve used it to insert Track numbers 01 to 18 against the relevant files but the Fuze still presents the files in the wrong order, so I think I’m missing the point somewhere…