Question

When I delete a managed object that contains image, stored as transformable value in external record, then I got crash and this error:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIImage _deleteExternalReferenceFromPermanentLocation]: unrecognized selector sent to instance 0xde49360' 

Answer 1

I answered to something similar in the Apple Developer forums.
I am guessing you have the external storage checkbox selected on that field in the data modeller.

There is a bug in that can be worked around. I did it like this:
Once you have updated your data, and saved the context, any attempt to delete it will raise this ‘unrecognized selector’ exception.
To force the correct object that can respond to the _deleteExternalReferenceFromPermanentLocation message, do this:

[[self managedObjectContext] refreshObject:myobject mergeChanges:NO];

The object turns into a fault. When you next access it, or delete it, the external data is deleted as expected as the correct object that wraps your external data will be pulled from the store and will correctly respond to _deleteExternalReferenceFromPermanentLocation.