My scene suddenly has a blue tint?

I'm working with Collab, the project is on my Mac and two Windows.

Suddenly on my Mac, the scene is tinted blue. I tried generating the baked scene light again, I reinstalled Unity, updated Unity to 2017.3.1p1, no matter what I do the scene is tinted blue. The actual lights are of course not blue and it works fine on the other computers.

I'm running out of ideas? Thanks so much.

Here's a pic, as you can see there's also a blue horizontal line in the middle that should NOT be there. (And it's not there on my other computers either.)