NSMergeConflict on iOS7

Question

I have updated my app to support iOS 7 and have been faced with the problem that on one of screens in my [context save]; I get the following error:

Answer 1

I got similar error, and in my case, locking NSPersistentStoreCoordinator worked.

[context.persistentStoreCoordinator lock];
[context performBlockAndWait:^{
   // do something
}];
[context.persistentStoreCoordinator unlock]

I don't know why it works, but I suspect NSManagedObjectContext's bug. I hope this will help.