User Profile

Ok I figured something out, and this line in kevdek's answer tipped me off: CoreData: sql: UPDATE ANSCKRECORDMETADATA SET ZENTITYID = 4 WHERE ZENTITYID = 3 I found similar logs in my debugging. It appears that CoreData wants *really badly* to have the entity IDs based on the entity names, sorted alphabetically. As such, if your new entity results in the shuffling of entity IDs, it seems that CloudKit fails the migration. On a hunch, I renamed my new entity from "Reminder" to "ZReminder", and the migration was successful. Surely there is a better solution.

Thanks @kevdek. Glad to know I'm not alone.