"Applications that can store documents in iCloud include Preview, TextEdit, Pages, Numbers, Keynote, GarageBand, and some third-party software such as "DayOne," "iA Writer," "MindNode," and perhaps others. If some or all of those applications are suddenly not working well, there may be a problem with iCloud synchronization.
Back up all data.
Open the iCloud preference pane in System Preferences and uncheck the box marked Documents & Data. See whether there's any improvement. If there is, continue.
Hold down the option key and select
Go ▹ Library
from the Finder menu bar. From the folder that opens, move this folder to the Desktop:
Mobile Documents (or any other item with a name beginning that way)
and move this folder to the Trash:
Re-enable Documents & Data, log out, log back in, and test. The folders should be recreated automatically. If the issue is resolved, delete the folder you moved to the Desktop.
If you continue to have the same problems, I suggest you contact iCloud Support."