Missing Mapping Model after editing the model

Question

I'm in the process of a manual core data migration and keep running into Cocoa Error 134140: NSMigrationMissingMappingModelError. I've noticed this happens any time I make any change to the model, even something as small as marking a property as optional. So far, the only solution I've found when this happens is to delete my mapping model and create a new mapping model. Are there any better, less tedious solutions?

Answer 1

There's a menu option to resolve this. If you update your model anytime after creating your mapping model just do the following:

1. Select the mapping model.
2. Choose Editor -> Refresh Data Models.