Why are some content sources missing from "Choose content"?

The list under “Choose content” isn’t a fixed menu. It’s built from what your connected account actually holds inside the date range you selected — so if a source like Mobile Uploads or Photos has nothing for those dates, it simply won’t be listed.

Try this first: widen the date range of your book and check the list again. Most of the time the missing sources reappear straight away.

If a source you know has content is still missing: go to your connections page, disconnect your account and reconnect it, then create the book again. That forces a fresh import and rebuilds the list from scratch.

You can create books from Facebook, Instagram (with a Professional account) and Dropbox.