Default Unity Sky box changed?

Question

so whenever I load up a new project in unity3d, the skybox is default to blue solid color,unlike how it originally was with a skybox with clouds and a sun in the sky, how do I set it back so the default skybox is the original one that unity comes with

thank you in advanced ;)

Update: here is a picture of what it looks like

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vs what it should look like:

Answer 1

In MainCamera GameObject change solid color (in Camera component) to skybox.

Go to Lighting tab >> Scene >> Environment Lighting >> Skybox and choose Default-Skybox material.