What does this Obj-C "unrecognized selector sent to instance" exception indicate?

Question

What does this mean?

* Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[NSPathStore2 hidesBottomBarWhenPushed]: unrecognized selector sent to instance 0x1cd3d0'

Answer 1

This means that a string is being sent a message meant for a view controller. Since it's hard to mistake one for the other in most cases, this usually indicates a memory management error where one object (the view controller in this case) has been deallocated and another has been put in its place.

Answer 2

That message indicates that you have tried to invoke an object by using a selector that the object does not recognize/handle.

In your example that means that hidesBottomBarWhenPushed is not handled by NSPathStore2 which, just like Chuck explained makes sense since NSPathStore2 is a private subclass of NSString and hidesBottomBarWhenPushed seems to be a selector meant for a view controller.

In short -> you are sending the selector to the wrong object.