I previously used the excellent tip for syncing all document types across my wife's Macbook Air and the family iMAC.
Using iCloud to sync multiple document types.
We updated both machines to Yosemite.
The folder in the sidebar disappeared, I recovered it from the Finder>Go(alt)>library menu but now the document folders are present but none of the files will open - error messages are corrupt files...
Interestingly I now how 2 mobile documents folders - 1 appears to be the newer iCloud Drive folder and the other the original folder I used to sync documents with a Mobile Documents followed by a 9 digit number (which I assume corresponds to my wife's iCloud account)
Any help would be greatly appreciated
Cheers
Paul