NSUnknownKeyException this class is not key value coding-compliant for the key-changing from Obj-C to Swift

Question

I know this question has been asked a lot but the answers do not work for me. For this class:

import UIKit

class ProfileViewController: UIViewController {
    @IBOutlet weak var bioTextView: UITextView!

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}

I have added an outlet from my storyboard to the bioTextView. There are no other outlets on this view in the storyboard, all I have done is add an outlet and nothing else and I get the error. There were other other outlets to an Objective-C file that I am replacing, and those outlets, along with the file, are deleted. I keep getting this error: Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<UIViewController 0x7fc86bc08700> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key bioTextView.'

Any answers with clear instructions not written for someone who already knows how to code in Xcode would be greatly appreciated.