Hello,
I hope that you can help with my problem. Somehow when I try to render a project using Vray sun the sky is not showing up. When I reopen the project and try to do an interactive render the clouds and the sky appear briefly and then it begins to re-render interactively and the whole sky disappears. I tried adding the texture “sky” map, and even with that it doesn’t show up. When I try rendering with and HDRI everything works fine.
Have you tried resetting to factory settings and rendering again?
Yes, same thing happens. I tried to past the object in a new sketchup file and same.
Since when did this problem appear? Has rendering ever worked correctly?
If you open a new tab and create only a box, is it rendered correctly?
Yesterday it was rendering fine with Light gen, I didn’t try using only sun, and each time before today. If I open another sketchup file and start rendering it works fine. Only today with this project (which is the same as yesterday, no changes) using sun and sky, the sky doesn’t appear but sun effects are visible.
No, it’s on. That’s what I checked first.
You should have a dome light showing in the lights - you just have sun.
To me it looks like a disabled environment or an inactive sky procedural map.
Thank you so much! My sky is back ON 
Do you have any solution on bringing Vray data in a couple of clicks? 
Sorry, but I need help again. When I was adjusting the sun position in an interactive render the sky was there, I rendered my project and while it was rendering the sky was present, but when it finished rendering and I saved the file I saw that it appears without the sky. I did a screenshot inside the vras yrender and you can see that the sky appears.
I think you moved something in the light mixing panel and “turned off” the sky there.