Originally Posted by Diana D
Mine does the same thing - I emailed Kobo about it and the response I got was, basically, the only way to stop that from happening is to move completed books to the "Deleted" folder in your account on the Kobo website. Apparently you can keep them in there for 30 days without losing them forever.
That seems kind of unfair (forcing me to choose between paying for a book and then losing it for good OR going through a time-consuming and clutter-making re-sync every time I update my library). Haven't heard back yet.
You won't lose the book, you'll always have the book in your purchase history which is i guess an archive of sorts. It will just be out of your library.