Do Anyone have this issue? From some weeks ago the forest sky seems totaly black in GG.

Looks ok to me, have you validated your files? might be missing or corrupted

Thanks
@GraPhiX How can I check that all files are ok? I tried to desinstall and install again from Steam, but it is not fix it yet.

might be a daft question but are you sure it is actually not appearing? try looking up, by default the sky is very dark and you will need to increase the brightness slider to see it well

I totally sure.

Additionally I realize that all my files are stored on steam cloud servers, that means, when I reinstall the GG app all my files are restored from there, so, it is not possible to do a clean installation. I think this because I desintalled and check that the folder was deleted. I reinstall again and all the folders were created again included also my own personal models files!!!

Finally I fixed it. The issue was regarding the image file names. One software changed the extension of the image files and put them in uppercase instead lowercase, (maybe Steam),

Updated information:
If I remove the file : forest.dbo the sky is again visible, maybe because GG is using the .x file instead, and generate a new .dbo file. But if I run again the same level. The sky is again black and I need again to remove the .dbo file if I want to see the sky correctly.

Solved! The issue was the extension of the image files in uppercase.