I've got an AVQueuePlayer which I'm creating from an array of 4 AVPlayerItems, and it all plays fine. I want to do something when the last item in the queue finishes playing, I've looked a load of answers on here and this is the one that looks most promising for what I want: The best way to execute code AFTER a sound has finished playing In my button handler i have this code: static const NSString *ItemStatusContext; [thePlayerItemA addObserver:self forKeyPath:@"status" options:0 context:&ItemStatusContext]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(playerItemDidReachEnd) name:AVPlayerItemDidPlayToEndTimeNotification object:thePlayerItemA]; theQueuePlayer = [AVQueuePlayer playerWithPlayerItem:thePlayerItemA]; [theQueuePlayer play]; and then I have a function to handle playerItemDidReachEnd: - (void)playerItemDidReachEnd:(NSNotification *)notification { // Do stuff here NSLog(@"IT REACHED THE END"); } But when I run this I get an Internal Inconsistency Exception: An -observeValueForKeyPath:ofObject:change:context: message was received but not handled. Key path: status Observed object: <AVPlayerItem: 0x735a130, asset = <AVURLAsset: 0x73559c0, URL = file://localhost/Users/mike/Library/Application%20Support/iPhone%20Simulator/5.0/Applications/A0DBEC13-2DA6-4887-B29D-B43A78E173B8/Phonics%2001.app/yes.mp3>> Change: { kind = 1; } What am I doing wrong?