NSCocoaErrorDomain Code: 134100

During development, this error can appear while adding pre populated data in a new project or after modifying entities in a CoreData model.

The model used to open the store is incompatible with the one used to create the store

Regardless of the reason, the solution is the same: Remove the app from your simulator and clean the project.

If it's happening during production, you will have to implement something like a migration mechanism.