I don’t usually blog about crashes etc but this one wasted me a few hours.  I was working on a iOS 8.4 project in Xcode 6.4.  Each time I edited the storyboard, Xcode would instantly crash.  However my colleague’s machine did not?  The only difference we could see (even after reinstalling Xcode) was I had also had Xcode 7.1 installed.  Usually this would be fine however something changed with the libraries it uses (PepperUICore).  It was only when I found this post, I saw the fix

https://forums.developer.apple.com/thread/21927

The fix, which worked for me was to run the following commands to make some symbolic links

sudo ln -s “/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 8.4.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/PepperUICore.framework” “/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 9.0.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks”

sudo ln -s “/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 8.4.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/SockPuppetGizmo.framework” “/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS 9.0.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks”