Xcode storyboard: Internal error. Please file a bug

Question

While editing in the storyboard, specifically assigning a view controller to a specific class, I suddenly encountered this error when I wanted to run the project.

Ma

Answer 1

None of the other answers worked for me. Here's what did.

1. Open the storyboard, select all and copy.
2. Create a new storyboard, paste.
3. Delete original storyboard.
4. Rename all references to old storyboard.

Build and run.