I had downloaded the Swift Book 4.0, it updated successfully on my iPhone but not on my Mac.

It did not even open the book. I followed the solution here, after I deleted the folder, I opened iBooks and it prompted me to update.

It then saved the updated book in updates folder but it still showed version 4 in iBooks. So I deleted the book again.

Now iBooks shows the book is updated, but it does not open. How do I fix this?