This happens due to an image that is far too big to be rendered. Normally, images higher or wider than 8000 pixels should be re-sampled automatically, but sometimes it happens that they get into an album without re-sampling.
What can I do to fix this?
First, check if there is enough storage space available on the C:\ drive. That is where the order file will be created on no matter the storage location of the album.
1. Open the folder with the saved photo book in Windows Explorer (Where can I find my saved projects?).
2. Look if on the bar with name, type, size etc. is also a column with dimensions.
3. If not, right-click on that bar. Select "Mehr", search for "Dimensionen" and select that.
4. Now there is a column "Dimensions". Click twice on that column to sort on dimensions (largest files first).
5. If there are files with a height or width > 8000, those are the ones that are giving trouble.
The only way to fix this is to resize the image in an external program, to make sure that the longest side is a maximum of 7999 pixels.