Swift3 Cocoa Storyboard Storyboard doesn't contain a controller with identifier 'MainWindow'

Question

In my project in cocoa have the same Problem as Can Poyrazoğlu in this Question: Storyboard doesn't contain a controller with identifier 'MainWindow' None of the advices help, included manually saving the project. It worked well - 3000 lines - until I began inserting code with NSTableView. The behavior is odd: I have some print statements in the TableView code for debugging. After a change in the code, the app runs but nothing is shown in the TableView exept the above line appears, but the printing does not show up in the console. Running again mostly works. The error message now apears AFTER the print output. Is this a timing issue? Storyboard ID is set correctly, I think. In other projects I never had to set such an ID Any help...

Answer 1

let mainViewController2 = self.storyboard?.instantiateViewController(withIdentifier: "mainview") as! mainview

in your case you forgot the class name so this error showing you.