Unreal Engine Crash with screenshot of OS wide glitch during

Hi all,

When I try to launch UE 4.13 on an iMac with Radeon r9 m380 2048 mb it freezes the system. We managed
to alt+tab of sorts into a browser window and all text was also glitchy like in the image. Does this mean our GPU on the iMac is below the requirements?

Thanks in advance,

Problem solved when upgraded to Sierra!