I was able to fix the problem by removing enum from my model. I had this enum: var goalType: GoalType = GoalType.regular enum GoalType: Codable { case regular case auxiliary case special } I made migration and deleted this entity from my model and the error stopped appearing.

I am having the same problem. I am able to do only the lightweight migration without the error.

I have the same problem, apparently there is a bug and the custom migration doesn't work if you are using CloudKit. I have the same situation and i am going to try lightweight migration and hope it will get fixed soon.

I wasn't missing anything. After my post on the forum suddenly I was able to enroll without any changes.

Thank you! I fulfill all the requirements. And I believe that Apple Support should be able to tell me if there is anything missing. But after your response everything started to working and I was able to enroll. Thank You very much for help.