I know it sounds obvious but...have you tried re-adjusting from your screen? Like auto-adjust to the source?
I had one similar problem once and that wasn't the first thing I tried...Sometimes we search for way more complicated solutions.
I've been trying to solve this for days now and I surrender. I feel like I have read everything I can understand.
I have a dual screen setup, both with different resolutions (one is 1920x1080 connected through a DP-VGA adapter) and the other one is 1280x1024 connected through DVI)...
I am currently finishing my update from a rock-solid stable Mountain Lion hackintosh to a new Windows 10 / El Capitan dual boot.
I am writing my little guide as a contribution when I am done.
This is my problem: when I first install El Capitan from the USB EVERYTHING is perfectly...