I have some audio books on my device, but several are sorted under 'Podcasts'.
It would be great if I could change this to 'Audio books', so that I will have all of my audio books in one place.
The drop-down menu (for media types) does not drop down, so I cannot change this now.
Please do the following:
Search for Device manager -> Universal serial bus devices -> iPod (your device) -> Properties -> Change settings -> Update driver (or Roll back driver) -> Browse -> show drivers on my PC -> Select usb mass storage device (or Apple ipod usb driver).
If the solution above did not help, refer to this troubleshooting guide for iPod corruption errors:
https://www.copytrans.net/support/how-to-fix-ipod-corruption-errors/