light disappear after building

hi, i’ve a problem with lights in ue4. I’ve placed the lights in my room and they are visible , but when i build the scene, lights disappear! They are not visible. I’ve tried to increase the power light but without results. After many tests i understand the problem is the mesh. So i’ve tried to modify the walls. I’ve check the box"double sided geometry" and in the panel light i’ve check the box “cast shadows double side”. In this way the ligjt are visible and correct. But the exterior light generate on my walls strange artifacts with the double sided geometry shadows activate.

So,

Double sided geometry and double sided shadows INACTIVE -----> light disappear after buiding

Double sided geometry and double sided shadows ACTIVE -----> light visible but strange artifacts on my walls(static mesh)

what can i do?

Hi,

can you show example screenshots before/after light build and tell what version of UE4 you use? also try make new raw template project and make some lights inside it to reproduce bug