For the longest time I kept getting LS-0014 Launch Error Code when trying to launch UE4 on my MacBook Pro. Someone on a forum suggested I “verify” the installation which I did. Once it was finished, NOW when I click launch, it crashes immediately. It’s been 5 months now with no help or fix! Very frustrating and quite unacceptable. alt text
Same for me. I was able to launch Unreal Editor 4.10.3 until I upgraded my MacBook Pro to High Sierra 10.13.3, XCode 8.3 and Unreal Editor 4.18.3
I think that the installation of UE 4.18.3 affected the earlier versions of Unreal Editor. Right now I have no problems to launch the Editor >= 4.16, but it will crash for any 4.7.x, 4.8.x, 4.9.x, 4.10.x version.
I tried to upgrade the older projects to a 4.18, but they crash as well. So I cannot run and use any older projects. ;-/