Unreal super slow after High Sierra upgrade

Before High Sierra upgrade Unreal was running very well, now it’s running so slow it’s almost unusable on I7 MacBook Pro 16GB RAM, SSD. Also fan is on all the time and system super hot.

Other applications also become unusable while UE4 running

Same issue for 4.17.2 & 4.18.

When UE4 has quit fan goes off and system back to normal.

Has anyone else seen this behaviour too, considering going back to previous OSX, but just want to make sure its a real issue?

Same here, slow and hot. Completely unusable.

Went back to Sierra. All the problems went away

High Sierra really breaks a lot of stuff.