Custom Map Skybox Issues

[Loam]

In trying to make a custom level, I copied the xml of "scrubby_hills_fall," made no changes, and placed it in the "Levels" folder (it was in the "Levels/challenge" folder) and renamed it "new_test." When I played it the skybox showed up as green/black checkers, and the ambient light was green.
This also happens with Sea Cliffs and Challenge Levels 11 and 12 (both completely unaltered).
I searched the forums, and everyone said to get the Skyboxes fix, which I did, along with Fixes, Painted Skyboxes, and Unlocked Default Levels (these are the only custom contents I have running), with no effect.

[Loam]

Okay, I got it to work by replacing what sky it uses. Still don't know why it wouldn't do that automatically; maybe because I had already loaded it before getting the Skyboxes fix?

[Thomason1005]

You could try deleting the cache with sumlauncher, so it needs to recompress your sky texture to dds
file/delete local data or sth like that

[Anton]

Once you had the issue with the skyboxes, you needed to clear the cache. If you installed SUMLauncher, you can do it there by going to the file menu and choosing "delete local files", then choose "Overgrowth Cache Files". Then, once you have the skyboxes installed, it will correctly generate the skybox you need.