So I recently redownloaded TW3 and its a clean installation with no mods. It was running 1000% perfectly for the first 2 days I was playing it, then suddenly when I tabbed out and back in the lighting had changed and now the sky and anything light blue or white turns to a solid teal colour. As you can see with the attached image. I've got a GTX 1080 with the latest drivers and I actually reverted back to the previous driver incase it was an issue with this driver. Tried messing around with all the in game settings and nothing has worked so far.

If anyone can shed some light on this issue I would greatly appreciate it as my next move if this fails is to just uninstall and leave it be.

Change to borderless window (for tabbing out reasons) and reboot your computer.

I appreciate the response, although I should have mentioned this issue occured while the game was already in Borderless Window.

The reboot was the important part.

There were many reboots since the issue occured a few days ago and they didn't help.

When I look at that image again it seems to be a reduced colour (16) image, much like you get with some old games when Windows forces a reduced colour palette because of system performance. What is your hardware and OS?

Windows 10 64 bit, GTX 1080 and i7 processor. Ive ran loads of games like this in ultra with no issues before.