CoreDataSaveFailure.m

NSError *error = nil;
if ([self.managedObjectContext save:&error] == NO) {
    NSAssert(NO, @"Save should not fail");
    [self showAlert];
}

- (void)showAlert {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Could Not Save Data"
                                                        message:@"There was a problem saving your data but it is not your fault. If you restart the app, you can try again. Please contact support (support@domain.com) to notify us of this issue."
                                                       delegate:self
                                              cancelButtonTitle:@"Ok"
                                              otherButtonTitles:nil];
    [alertView show];
}

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {
    abort();
}