Fix an Unauthorized Media error in iBooks Author
If you’ve created a book that contains video files in iBooks Author, you might see an Unauthorized Media error when you try to publish.
You can follow the steps below to fix the error and publish the book.
Quit iBooks Author.
Open the Terminal app, then enter
defaults write com.apple.iBooksAuthor SFDisableSingleFileFormat YES
Open iBooks Author.
Open the document that showed the Unauthorized Media error when you tried to publish.
Make a minor edit in the document, save the document, and then close the document.
Reopen the document, and try again to publish.