Hello there,
I recently started to learn UE with the version 4.11.
I know that lots of topics talked about it, but I can’t fix my problem and I’m going to turn crazy ! 
Here is the problem :
When I build my scene, the following error comes up
The problem is that I used ContentBrowser/Props/MaterialSphere and did not touch the settings of the mesh before the error came up.
I searched on google and find some solutions.
I tried this one A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums
But when I try to generate lightmap UVs in the build settings, then it’s not generated properly (I think, there is some red in the UV channel 1)
The fact is that I can’t figure out what is the problem, what could bring on the error and why the lightmap UVs are not generated properly by UE ?
I hope that someone could help me solving/explain it, thanks ! 