Reply To: One Hundred and Twelve Business Cards

The yellow triangle indicates the file has been edited outside the Book, i.e., when the book is not open or minimised. Open the file through the book save and close. If there is still a yellow triangle it means that more pages have been added to that document and the page numbering has not been updated.

Since these are business cards you don't need to worry about the page numbers. So you can go to the Sub Menu (top right of the Book Panel there's a sub menu under the triangle)

Go to Book OPtions and turn off automatically update.

You can export the book to PDF – then in Acrobat choose Document>Extract Pages and then you can choose to extract all the pages to separate files.