Unable to sync PDFs to iPhone over USB

The pdfs that were transferred from my previous mac to the new M1 did appear in the Books app but were not visible

in the Books tab of the iPhone sync window (None appeared : neither those in Books on the iphone, nor

those in Books on the mac M1 ).

We solved this by an elaborate and not very elegant process of removing them and

reintegrating them :

• First we deleted a few finder prefs in the ~library folder ( did not have time to write down : I remember com.apple.finder.plist, Finder_long number.plist, FinderSyncRoots.plist
  • You might try without this I suppose.
• Create an empty folder -e.g "PDF-from-books"-somewhere safe, copy all the pdfs :
  • Drag and drop the pdfs from the Books App window to this PDF-from-books finder window .
• You see a sort of bullet icon next to the files as they are copied !! Caveat : do not copy that about40 at a time ( I had 643) otherwise Books freezes (not so elegant ... I warned you)
• Check they are all now in PDF-from-books, remove them all from Books App on the Mac
• Once Books is empty put them back by dragging them from PDF-from-books onto Books app icon
  • In fact we put a few back first and synced to see if this worked see below ( not sure this is necessary )
• In the Books tab of the sync window in finder, check the pdfs you want to be synced on the iphone. probably go progressively if you have a lot. I think we did a few at a time and then all
  • The pdfs on your iPhone appear in this list too ( this is new behaviour to me... not bad but a better interface should show them in some different appearance (icon ? different font or italicised?)
• Now you can try to sync
  • NB we had to skip syncing photos for it to complete - othewise it stayed forever stuck (waiting for elements to copy)
    • To skip syncing photos you have to click real long ( 3-5 sec) and WAIT. Do not press again until you see nex step as this click might be taken into account on the next step and skip pdfs ;-(
• It did not fully work at first : a few pdfs seemed to be problematic and had to be unclicked or removed from the Books app on either end.

I hope I did not forget any step. But I'm sure this can help some that spent a lot of time on this issue .

Now I enjoy my pdfs on the iPhone (routes for hiking, nature identification books etc.)

The syncing method is the same.

I spent over 6 hours on-line with Applecare+ people on this issue. It seems to be a bit touchy but now i've got all my pdfs on my iPhone. I will try and summarize here. Sorry for my poor english as it is not my language.

A useful diagnostic step :

• Check in another session if Books after adding any one or two pdfs is ready to sync in the Books tab of the iPhone sync window (now in finder, previously in iTunes. If yes the problem is in your session. DO NOT sync.

B This is is how we untangled it. I appears that there were many issues (I consider they should be corrected event if they don't qualify as bugs ?)

• When repeatedly syncing to test , if you've done it recently, you can skip the backup of the iphone, but it is very unresponsive :
  • you have to click real long ( 3-5 sec) and WAIT. Do not press immediately as this click might be taken into account on the next step and skip photos or pdfs ;-(
• Not sure about this but worth checking : The system did not warn of sync options that prevent all syncing . Uncheck if needed option for Books to be synced in iCloud - on both the Mac and the iPhone. (migration and user options should not allow choices that block the whole sync process : Probably many users would fîddle all sort of options when sync does not work properly )
• The migration process was faulty : the pdfs that were transferred from my previous Mac to the new M1 did appear in the Books app but were not visible in the Books tab of the iPhone sync window. None appeared : neither those in Books on the iphone, nor those in Books on the mac M1 ).

C The whole process will be described in a further reply below but amounts to removing all pdfs from the Mac Books app, reloading them, and suspending the photos syncing on that session to allow the full sync of the pdfs to the iphone.

Seems odd that this is needed with the very powerful machines on both ends (is 643 pdfs and a few more photos to add to a 44k collection really such a problem that it tires half-way as the applecare person suggested ... on an iphone built to handle 256 Gb of various media ? Anyhow this is worth trying and thanks to applecare for helping here

Thanks for this reply brbo.

This Iphone has 166.95 Gb free … The mac has 1.48 Tb free

It is interesting to know that these same pdf synced happily from my previous MacBookAire 2013 into an iPhone 7plus.

I'm not implying that M1 and the corresponding system version or the upgrade process is not yet mature, but it cannot be excluded ;-))

Other Ideas ?