Recently I have been seeing this error when saving to core data. Does this mean that the phone itself is full and cannot save anymore data, is there anyway to check if the disk is full and present some kind of notification to the user or prevent saving all together if it is full?
This NSPersistentStoreCoordinator has no persistent stores (disk full). It cannot perform a save operation.
You need to catch the error, handle it gracefully, and inform the user that the device has no space to store whatever it is you want to store.
You could do a check when you launch the app or return from background: how much space available. If not enough (including some margin), notify user of the potential problem. That's better than letting him enter data and then fail to save.