[UINavigationController retain]: message sent to deallocated instance

Question

My application crashes when simulating Memory warning in simulator with error:

[UINavigationController retain]: message sent to deallocated instance<

Answer 1

Finally after days of investigations I've found a reason to all these crashes including the one described in "iOS memory warning sent to deallocated UIViewController"

The problem came out from PHAirViewController project. I still did not find out a real reason, but simply commenting out - (void)dealloc function in PHAirViewController.m file did the magic.

The main headache I got when was running Instruments to detect NSZombies. All traces were pointing to system classes like UINavigationController, UIImagePickerViewController etc... Due to this I started disabling ARC for parent controllers. In some places it helped but in some it didn't.

After a lot of voodoo I found out that every class (including system classes) was implementing UIViewCOntroller(PHAirViewController) Category and though - (void)dealloc function was always called on dismissing them.

Now the only thing left is to understand why this function is generating NSZombies. The interesting thing is that just commenting its content (which have only one line: self.phSwipeHandler = nil) does not have the same effect.