"[CALayer release]: message sent to deallocated instance" in UIViewController

Issue

I have a MapView in an UIViewController. When I try to load the view after its viewDidUnload it crashes with this message:

-[CALayer release]: message sent to deallocated instance 0x29aea0

I think I do all the necessary things that I should do i the viewDidUnload:

- (void)viewDidUnload {

    [super viewDidUnload];

    locationManager.delegate = nil;
    [locationManager release];
    locationManager = nil;

    mapView.delegate = nil;
    [mapView release];
    mapView = nil;
}

My MapView is in an UIView configured in a xib-file. My VC is never deallocated.

I have been googling around for a while now but I can't find the answer.

Edit

 - (void)viewDidLoad {

    [super viewDidLoad];

    locationManager = [[CLLocationManager alloc] init];
    [locationManager setDelegate:self];
    [locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
    [locationManager startUpdatingLocation];

    [label setFont:[UIFont fontWithName:@"Sansation" size:28]];
    [label setShadowOffset:CGSizeMake(0, 1)];
    [label setShadowColor:[UIColor grayColor]];
    self.navigationItem.titleView = labelView;
    [label release];
    [labelView release];

    UIBarButtonItem *checkInButton = [[UIBarButtonItem alloc] initWithTitle:@"Checka In" style:UIBarButtonItemStylePlain target:self action:@selector(checkIn)];
    [[self navigationItem] setRightBarButtonItem:checkInButton];
    [checkInButton release];

    UIBarButtonItem *clueListButton = [[UIBarButtonItem alloc] initWithTitle:@"Ledtrådar" style:UIBarButtonItemStylePlain target:self action:@selector(cluesDown)];
    [[self navigationItem] setLeftBarButtonItem:clueListButton];
    [clueListButton release];

    UINavigationBar *bar = [self.navigationController navigationBar]; 
    [bar setTintColor:[UIColor colorWithRed:0.06 green:0.58 blue:0.88 alpha:1]]; 
}

"labelView" and "label" are IBOutlets.

Solution

Since you have neither allocated nor retained label and labelView in your viewDidLoad method you may not release them here (you are overreleasing them).

Answered By - DarkDust