Whenever I try to use the Storyboard Preview feature as part of the Preview Assistant Editor in Xcode, the whole program just force closes each time. However, there is nothing wrong with the code as it runs just fine in simulator.
The message I get simply states: "Xcode closed unexpectedly".
OS X Version: 10.11.6
Xcode version: 7.3.1
I have had the same problem and the only thing that solved it for me was to completely uninstall and remove Xcode and the to reinstall it again.
This is the stops you do to uninstall Xcode you need to remove: