I was using one of my Windows 10 Virtual Machines earlier and the profile lost all of its colour. It went grey (or gray…Which to use?!). It looked like this:

…instead of:

Just a bit strange I thought. Anyway, after some digging around it turns out Windows 10 has a set of colour filters to assist people who struggle to see certain colours. Somehow I’d managed to turn it on.
It’s simple to toggle – simply use Windows Key+ctrl+c and it’ll toggle between the two.
You can also get to it through the Control Panel – go to ‘Ease of Access’ and you’ll see it in there under ‘Color Filters’. Well you learn something new every day, don’t you?