Why does unreal freeze when you build light?

Hello Rhinoskin

Interesting. Did you tried to build lighting with very simple setup. Like one box one ground mesh with basic lighting setup?
If not can you try that and let us know please? You can also check the settings Under World Settings > Lightmass > Lightmaps > Compress Lightmaps is it checked or unchecked. If you are not compressing your light maps, they can be very big problem in large scenes. Last, maybe your light map resoulution for every object is too high(on your problem scene). Can you try to adjust them too?

Thank you.

When ever I try light build my scene Unreal used all 48GB of ram and freezes my computer.

Thank you. I actually had to clean out the Binaries folder for it to stop hanging. However I have the same scene in 4.13 and it doesn’t not use all the RAM I have and hang. The Issue seems only in 4.16.

I have 48GB of RAM with Dual Xeons with a total of 24 cores and it just uses all 48GB with nothing else running and hence does not allow for a light build.

Since the issue is not present in ver 4.13 I will continue to use 4.13