iBooks not syncing between iPad and iPhone

I had this problem too and was puzzled by it but managed to find the solution:

What you need to do is go to the device where files are not being syncronized and go to Settings>iCloud and then switch off iCloud, wait a moment, then switch it on again. If this doesn't work then do the same for the iBook switch under the iCould settings. Once you switch both back on again, it will refresh and all your saved files will be restored. Hope that helps!

I too have the same issue. I turned on and off iCloud on both devices a number of times. Turned off and on iBooks under iCloud on both devices a number of times. Turned off and on iBooks sync properties a number of times, again on both devices. Signed on and off from iBooks a number of times, again on both device. Even uninstalled and reinstalled iBooks a number of times, but nothing helped and now I am going to move my PDFs to Amazon or Adobe as they are far far better and easy to use. They have been designed better and have been tested enough that end users do face such issues which eats away hours together with no results. I mean, this should have been fai simple, but it seems Apple cares about only the books which users buy from iBooks and not the personal PDFs as they bring zero monetary value for Apple. This feature has been broken for years now and I know it’s not gonna fix. Good luck to us...

I had a similar problem: books won't sync on my iPad (but they did on my Mac and iPhone). After trying different things, what really worked for me was deleting the iBooks app on my iPad and downloading it again from the AppStore. Hope this helps.

Unless you are using iCloud Drive for the iBooks app the PDFs won't copy via the cloud between your devices - the 'sync collections' setting doesn't copy items between devices, all it does is if you have the same PDF or book on both devices and you move it into a collection on one of the devices, it will be moved into the same collection on the other device.

If you want to use iCloud Drive to make your PDFs available in the cloud (I don't use it so I don't know if there are downsides of it) : Use iCloud Drive or iBooks to access your PDF files, ePub files, and books - Apple Support

For your audiobooks (those not bought from iTunes) you will have to sync them onto each device that you want them on.

Same thing happened to me when I copied PDF from Microsoft OneNote to iBooks on my iPad. I turned on and off iCloud. Turned on and off iBooks under iCloud Drive a number of times. Turned off and on iBooks sync properties a number of times. Signed on and off from iBooks a number of times. Even uninstalled and reinstalled iBooks. Nothing worked. Conclusion, iBooks doesn't sync PDF when you copy them from OneNote, you'll have to copy them from somewhere else.

This solved it for me.

Use iCloud Drive or iBooks to access your PDF files, ePub files, and books - Apple Support

Make sure iCloud Drive has iBooks turned on in your Mac settings

System Prefs > iCloud > iCloud Drive > Options

Thank you...after an hour of getting nowhere...this did the trick In seconds!

Thank you!!! It worked! First time I find a real solution to a problem in this site! Thanks for your help and time! 🙂

I was having the same problem. I did delete iBooks and then reinstalled it, it is fine now.

Could you perhaps have a second Apple ID that is connected to your other device?

This advice worked perfectly!! Thank You!

Go into iCloud in settings. Deselect iBooks back up and reselect. Then go back into iBooks app and everything should appear. I was having problems iPhone and iPads syncing -this worked.