Failed to connect (storyboard) outlet from (NSApplication) to (NSNibExternalObjectPlaceholder) error in Cocoa and storyboard

Question

I\'ve tried to build a sample Cocoa app on which I want to connect UI components put on storyboard to ViewController.swift as either an IBOutlet or

Answer 1

While the answer above correctly states that this isn't the reason for compilation issues, I thought that I would clarify for those who are just looking to eliminate the warning messages altogether. This was what I was looking for when I found this page.

When you are building your actions and some of the actions change, or get deleted in the storyboard, the outlets remain. Select the controller/window where the older unused actions used to be and you will still see them in the outlets segment of the storyboard within the attributes tab. Remove those old actions/outlets there and then the warning disappear.

Look for duplicates between the ViewController and the File's Owner. One or both might be holding on to these objects when they shouldn't be. Removing those will remove these soft warnings.