I am having the same issue described at this address <http://www.cocoabuilder.com/archive/cocoa/288659-iphone-nsmanagedobjectcontext-save-doesn-crash-but-breaks-on-objc-exception-throw.html>

I am debugging an application that uses Core Data with multithreading, and I have a breakpoint on objc\_exception\_throw and it hits this breakpoint in the call to save. (line 2 in code)

```
        NSError *error = nil;
        [self.managedObjectContext save:&error];
        if (error) {
            NSLog(@"Error : %@",error);
        }

```

I don't have any thing that is logged.
I am using Xcode 4 with ios 4.0 -> 4.3. I think this is not related to Xcode/iOS version.