Thanks for your answer Mr Akash It´s the first time I have this problem. Frequently I made photobooks with the same computer, the same MOS and the same Lightroom. Mac Os Version 10.15.6. Lightroom version 2006-2020: 10.0 (202010011851-ef6045e0); Camera Raw 13.0 As you can see in the image, if I made a new album I don´t have problem to transfer the photo, but in the original book with 256 photos its impossible. Thanks for your help
Thank you all.Problem solved by following your advice.I have changed the sort order in the Book I am doing and I can now transfer new photos.You have to change from a custom order to another type of order.