Huuuh!!!
How can I fix this?! I even uninstalled Unity and decreased the version, but still no luck… My Terrain dissapears if I make a new one too, but this terrain I have been working for days and now its under the ground/gone???
Regards,
Apasalic.
its not gone
your are just below the terrain with the cam from what I see, not above it 
Ehm how can you explain this then:
This is a fresh new terrain, can you see it? No you cant…
because you are still below the terrain and looking up.
Maybe some backface culling ?
