Xcode 8 hangs / unresponsive when opening storyboard

Question

I\'ve recently upgraded to Xcode 8 and updated my project to Swift 3. All worked fine for a little while. Storyboard loading has always been slow (even when still running Xcode

Answer 1

I've had this issue multiple times. Usually, Bonan's solution works for me. On the two occasions in which it didn't, the issue seemed to be with a toolbar bar I was using. When I isolated the offending tool bar by panning over to a place on the storyboard where the toolbar's view controller was not visible on my screen anymore, instantly the storyboard speeds back up. I then panned back to the bad view controller and deleted the toolbar before the system slowed down again. I'm sure there's a way to fix the toolbar rather than deleting it, though I don't know what that is. I had the Simulated Metrics value set to 'inferred' as described above by Luke Van In so it must have been a different problem.