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

OK, solved the problem by removing all core data files from Xcode, reading them and setting the source and destination of the mapping model again.

Damn you Xcode!