One of the common errors when using CoreData is

*** Terminating app due to uncaught exception 'NSObjectInaccessibleException', reason: 'CoreData could not fulfill a fault for '0x10123456 <x-coredata://3E1F9B1C-46BE-49F8-A3ED-1234567BF0/Event/p42>

This is what happened:

CoreData tried to access the entity, but it could not even fulfill a fault. It is most likely because the entity is no longer around, aka deleted.

Read Apple CoreData troubleshooting guide on such object life-cycle problem.

I have encountered this more than once when using NSFetchedResultsController and with Magical Record.

• NSFetchedResultsController is using it’s a context for fetching the entities

• Magical Record is using another context to update/delete some entities

• When Magical Record deletes an entity, NSFetchedResultsController has the (crashing) error

The solution is to be careful with using multiple contexts and avoid the scenario.

Duh.

Okay, let me give you a more meaningful workaround: If you are deleting, you might want to “mark for delete” instead. Then let NSFetchedResultsController to run at some interval to remove the marked entities.