Until it isn’t.
Or I receive the error message “Bad Audiobook Part: This audiobook part cannot be played because of a bad file.”
Or the audiobook won’t open at all.
Don’t panic. It is easy to fix these problems. Something probably happened in the downloading process and you need to delete the bad file(s) and redownload.
This pretty much fixes the problem. Except if you are out running and have to wait until you get home to redownload it. For that, I sympathize and apologize.