If, in haste, you inadvertently add a storyboard file to your Mac or iOS project from the wrong platform palette, you’ll end up with a storyboard that compiles and installs into the app bundle, but which products cryptic errors upon building and running. For example, a Mac storyboard lost in an iOS world:

*** Assertion failure in -[UIStoryboard initWithBundle:storyboardFileName:identifierToNibNameMap:designatedEntryPointIdentifier:], /SourceCache/UIKit_Sim/UIKit-3347.44.1/UIStoryboard.m:52

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid parameter not satisfying: nibNameMap != nil'

The assertion above occurs when, internally to UIStoryboard, the Info.plist for your compiled “.storyboardc” file is consulted to determine its constituent “.nib” files. In the Mac case, the keys for storyboard Info.plist entries have an “NS” prefix, e.g. NSViewControllerIdentifiersToNibNames, whereas on iOS, it goes hunting for a UI-prefixed key: UIViewControllerIdentifiersToNibNames.

Granted, as soon as you proceeded to the next step, trying to populate the storyboard with UI elements that make sense for the platform, you would probably figure out your mistake. But if you’re just trying to get the ball rolling and end up immediately scratching your head over the failure, hopefully this blog post will have helped you figure out more quickly what was wrong.

I don’t think there’s any official way to change a created storyboard’s platform target. Best bet if you run into this is to delete the storyboard and recreate it from scratch, taking care to select the file template from the appropriate platform in Xcode’s “New File” panel.