Skyboxes painted with black spots in Unity 5

Questions & Answers
1

After upgrade to Unity 5, the areas which were bright white in Skybox are now painted black. Any ideas?

2

Here is what fixed it for me. Go find what skybox you are using. Search for it in your assets. You will see an error message: "This texture contains alpha, but is not RGBM (incompatible with HDR). Luckily, there is a ‘Fix Now’ button.

After hitting each ‘Fix Now’ the problem disappeared.

3

Are you talking about the default Skyboxed from unity Standard Assets or your own custom made skybox? There is a new default skybox for any scene but the old system is still the same. Here.

And if you want to create your own skybox, here.

Don’t forget: if you have a Skybox assigned to a Camera, make sure to set the Camera’s Clear mode to Skybox.

Hope it helps.