Vertical Line on late 2013 iMac 21.5
I was hoping for some guidance on how to fix my computers screen. It has the vertical line that appeared on it this morning. How do I fix the issue?
iMac 21.5", macOS 10.15
Try resetting the NVRAM and restarting in Safe Mode, if neither fix it then please create a new user account (call it test account). In the Test account see if the problem is still there. If it is that mean you have a hardware issue, likely a failing GPU.