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 came across the same problem with one nib in Xcode 8.1.

Having "Top Bar" and/or "Bottom Bar" set to anything but "Inferred" caused Xcode to slow down to a crawl. Changing this to "Inferred" brings performance back to normal, with the downside that it removes the bars in the preview.