I have started a new app a few days ago and began working with the simulator to test it. I started as an empty project and manually added the storyboard. The simulator build
I thought you may have deleted the storyboard and decided to use a .xib file on initial app launch. In this scenario, Xcode would try to find a nonexistent storyboard.
For this case, click on the Project > Info > Custom iOS Target Properties and delete this key value pair:
Main storyboard file base name