Hello,
I was just working on functionality when I switched back to my Map viewport and noticed everything tinted green.
This was a surprise, since I didn’t do any changes to the map or any of the visual models. This happened once before with another project, but it was resolved when I pulled the project from git.
I built lighting 3 times, but nothing changed.
Here is an image of the problem
Thank you for your time,
suzi9spal
-make sure that you have set your view mode to “lit”
-do you use any post process volumes? -> delete them and see what happens
-set your scalability settings to “epic”
-do you get the same effect in the template map? 
The view mode is set to lit, I’m not using any post processing volumes and my scalabilitysettings are already on epic. Yes, I get the same effect in the template map.
If you’re using nVidia GeForce there are settings for color adjustment (nVidia Control Panel -> Display ->Adjust desktop color settings). Perhaps it’s changed. Try to restore to defaults.
-post your specs
-make sure that you use the latest graphic diver
-which engine version do you use? (4.9?)
-report it on answerhub: https://answers.unrealengine/