View is not in the window hierarchy

I'm revisiting a project I haven't worked on for a while and the first time I've run the project in simulator I'm getting an error I can't work out.

I have a collection view and each cell links to a detailed view controller. This used to work fine but now when I click on a cell I get the following error

Attempt to present "Detailed view" on "Collection View" whose view is not in the window hierarchy!

How can the 'didSelectItemAtIndexPath' be firing to instigate the segue if the view is not in the window hierarchy? This is the code that is called and println statement is printed so I know the code is being read. I've also checked and the segue names are correct.

  func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {

    switch (indexPath.item) {
    case 0:
      performSegueWithIdentifier("showMonth", sender: self)
      println("cell pressed")
      break;

    case 1:
      performSegueWithIdentifier("showPromotions", sender: self)
      println("cell pressed")      
      break;

    case 2:
      performSegueWithIdentifier("showRank", sender: self)
      println("cell pressed")   
      break;

    default:
      break;
    }

  }

It always used to work fine which I why I'm confused.