Help me understand these error messages?

Hi, very new to UE4
Im working on a small project, following along with this youtube tutorial

Ive attached a screenshot of a set of error messages i received when I attempted to execute a lighting build.
error log.JPG

Maybe someone can help me understand these error messages?
They all seem to allude to the size of the scene, but its really not that big.
One error says “lightmass crashed” because lack of memory. But my computer should be handling this no problem!
I have an intel i7 at 3.5 ghz, 16 g memory, 64 bit OS windows 10

The scene also seems slightly laggy when I rotate and move it.
this scene cant be much larger than the scene the person is building in the video and Im positive it doesnt even compare to the levels that get built with this engine.

I do have UE loaded on a seperate drive from the main C: and the storage is on a third drive but I cant imagine that is an issue??

Thanks for reading