Can't find mapping model for migration - UIManagedDocument Core Data Migration

Question

I have two versions of my model Model001.xcdatamodel and Model002.xcdatamodel. These two are in the Model.xcdatamodeld bundle. I also have

Answer 1

You are not allowed to make any changes to the source/destination model after you have created the mapping models.

If you do make some changes,

• mappingModelFromBundles:forSourceModel:destinationModel: will not be able to find the mapping model file
• addPersistentStoreWithType:configuration:URL:options:error: with {NSInferMappingModelAutomaticallyOption: @NO} will report an error "Can't find mapping model for migration"
• migrateStoreFromURL:type:options:withMappingModel:toDestinationURL:destinationType:destinationOptions:error: will report an error "Mismatch between mapping and source/destination models"

So, just recreate the mapping model and copy every change you made in the old one.