how to remove vertical colorless line Macbook Air
Hello, i have a small problem from the last security updade (before that i didn't have a second profile (Guest Profile), since i dont need one i deactivated from the main settings and now i have just one main profile). But i still have an invisible vertical line that cuts the desktop/screen in half. Every time when i watch a full screen video in youtube i see that line or i go in main menu i see it. Can you please tell me how to get it off?
p.s. my brother has the same notebook, but he doesn't have that line. Thank you.
MacBook Air (13-inch Mid 2013), OS X Yosemite (10.10.3)