There is another question about generic command failures in Xcode, but I want to specifically ask about the "LinkStoryboards" command. This build error occurred after deleting a storyboard from my project and no amount of cleaning or restarting Xcode would help.
A LinkStoryboards failure means that the compiler could not find a storyboard used in a Storyboard Reference.
To fix my particular issue, I had to locate any Storyboard References to my deleted storyboard and delete those references.