Thanks. Looks like app might be stuck at very beginning (although I cannot be 100% sure), processing some system events, before even getting to our code 
I don’t have any idea what can be wrong, I’m afraid, so I’ll have to ask you to try a few more things.
- Do you have any external hardware connected to your Mac? If you do, could you retry after disconnecting them?
- Maybe some software is somehow conflicting with our app, so maybe you could try quitting everything, restarting your Mac and trying launching Unreal Engine app with no other apps running.
- Do you have UnrealEngineLauncher folder in your Documents folder?
Also, how long did you wait before giving up and force quitting app? I guess you gave it at least few minutes, but want to make sure.
Thanks!