I have had multiple users of my app report these error codes, though I can't reproduce the problem. I'm hoping someone on the Core Data + CloudKit team can escalate this to the top of their priority list... I have users that can't access any of their data on a new device because the import fails over and over again. What do I tell them? Even if I could wrap my head around the suggested workaround of syncing images with CloudKit directly, it doesn't sound like that would help users whose existing databases simply will not sync. I have people staring at an empty tableview because nothing will appear and they think their data has been erased. That's a pretty significant problem and calls into question the reliability of Apple's syncing solutions. In my data model, images are stored as separate entities specifically to avoid this situation, and yet here we are. Any cloud syncing solution should be able to handle a large number of images. I'd imagine most of my users have less than 100, and I even downscale them a bit! I don't mean to sound combative -- I'm sure the CloudKit team is diligently working through a large to-do list, but I would greatly appreciate an official response to this issue.

What does your Item struct/class look like? The error message seems to imply that "content" isn't a property of Item...