I used to have all my view controllers in the same storyboard, I decided that makes sense to split up the storyboards so I created a new storyboard file New File -> User Interface -> StoryBoard, cut all the controllers related with the user management (Login, register, password recover ...) and pasted them in the new file
Now when I call storyboard.instantiateViewControllerWithIdentifier("LoginViewController") it crashes with the following error:
'Storyboard (<UIStoryboard: 0x...>) doesn't contain a view
controller with identifier 'LoginViewController''
How can I solve that?

let storyboard2 = UIStoryboard(name: ..., bundle: ...)