[BillHoney]

My 2nd IPad has got in a complete knot with sync. 
macOS & iPad 1 are OK 

I've removed the app , signed out of iCloud. 
re-signed into iCloud & downloaded the app from appstore again. 

from an empty library,  I go to .../sync library
choose iCloud folder & update device. 

The pdfs & library appear to download OK & appear in the library, 
but when I go to open them I get "blah.pdf does not exist"

if I try to sync a second time, I get :
Error Encountered transferring files:
file:///private/var/mobile/Libraryt/Mobile%20Documents/ICloud~MobileSheets/Documents//blah.pdf 

Any ideas ??

Version 3.9.3. iOS 18