If your app becomes unresponsive (crashed) and you get an error that says: "Signal SIGBART" with a message about "Terminating with uncaught exception" in the debug area like this:
You can solve this issue using the following steps:
1. Scroll to the top of the debug message area.
2. Check the reason for the crash:
3. If it says "this class is not key value coding-compliant" then continue to step 4. If it says something else, try copy and pasting the reason into Google.
4. Right-click on all the UI elements in the Main.storyboard to find the connection that the error message is referring to:
5. Click on the x next to the connection to break it.
6. Re-create any IBOutlets or IBActions that you require by dragging and dropping.