Missing proxy for identifier UIStoryboardPlaceholder [duplicate]

Question

Hi I seem to have stumbled upon weird thing while developing a storyboard app.

My app is halted right after splash screen and in console I get error message:

Missing proxy for identifier UIStoryboardPlaceholder

Now, if I try to let the app continue running, I get new messages into console, which I believe are related to the fact, that there is something wrong with the first error message

*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason:
 '[<IntroViewController 0x6e35f40> setValue:forUndefinedKey:]: 
this class is not key value coding-compliant for the key sceneViewController.

What is strange I get this error only when working with iOs 5.1 Simulator. It works fine on iOs 6 simulator and also on devices with both iOs 6 and iOs 5.1

I tried to find answer, but google says it could not find any results for the word UIStoryboardPlaceholder, let alone the whole error message. I made sure, I don't have the word 'UIStoryboardPlaceholder' anywhere within my xcode project(not even inside nib files) and also there's nowhere mentioned 'sceneViewController'. Any idea what might be wrong?

EDIT: I tried to reset simulator and cleaning project, but to no avail

Answer 1

We had the same problem: a view controller in a storyboard file with its interface defined in a separate XIB file. (Using Xcode 6.3.1, iOS 8.3 and Swift 1.2.)

We are using Swift so we had added the @objc() declaration to the class declaration:

@objc(TestViewController) class TestViewController: UIViewController

We could instantiate the view controller just fine from another view controller using self.storyboard?.instantiateViewControllerWithIdentifier( "TestViewController" ) but when presenting the view controller (using self.presentViewController( viewController, animated: true, completion: nil )) the app crashed with the same "missing proxy" and "not key value coding-compliant for the key sceneViewController" error.

Our solution which we found after much frustrated trial-and-error-like debugging was simply make sure the view controller's Storyboard ID in the storyboard file is not the same as the class name.

When we renamed the Storyboard ID from "TestViewController" to "testViewController" (only difference being the lower-case first letter), everything worked…

Strange? You betcha, but everything seems to be working now.