¡¡SOS!! Skyboxes problem!!

Hi everyone!

I've got a problem with skyboxes from standard assets in Unity. I'm working on a project that combines Unity and Oculus RIft.

When I try to visualise my scene and look at the sky, the clouds are duplicate. I see one of them very clear and the other is next to the first one and its appearance is a bit transparent.

I tried to change the format of the whole pictures from "compressed" to "truecolor" but it didn't change. I saw skybox in a new project and it shows me the same. In an older project too.

Can somebody help me?

Thanks!!