If a book order appears to have finished uploading, and you try to quit Aperture, you may sometimes see a message that says the order is still in progress.
When you place the order, a progress bar says "Exporting Book... ." That actually represents the status of creation of the PDF file that will be uploaded to Apple Print Services, not the status of the upload itself. While the upload is in progress, you see this background task indicator in the control bar:
If you try to quit Aperture while the upload is in progress, you see this message:
Please Wait
You cannot quit the application until you have been notified that the current order is complete.
To see the status of the upload, choose Window > Show Task List... . Don't be concerned if it says 0% for a long time—your order is actually uploading. When the task list indicates that the file is completely uploaded, you can safely quit Aperture.
Note: The progress indicator shown above, as well as the task list entry for the book order, will only appear in Aperture 1.0.1 or later.