When I delete a book, BookyAI says the Trash would not take it. What does that mean?

Sometimes the Trash or Recycle Bin refuses a folder, for example when the books are on a network drive or in a synced cloud folder. From version 1.9.22, BookyAI then deletes nothing by itself: it tells you that the Trash refused the book and that nothing has been deleted, and asks whether to delete it permanently instead. Permanent deletion cannot be undone. If you want to keep a copy, press Cancel, open the book's folder from the book's page (Files) and copy it somewhere safe first.