Since upgrading to macOS10.12.4 I note white flashing lines when playing video content (i.e. BBC news, youtube, etc). Occasionally i see the screen flashing when I have a darker background. Anyone else out there with the same problem?
Please try this, if you have not already.
Go step by step and test.
1. Start up in Safe Mode. https://support.apple.com/kb/PH21875?locale=en_US
2. Repair Disk. https://support.apple.com/kb/PH22243?locale=en_US
3. Reset NVRAM/PRAM. http://support.apple.com/kb/PH18761
4. Reset SMC. Choose the method for “On Mac notebooks with non-removable battery”.
Thanks a million. resetting SMC and NVRAM seems to have worked, problem solved :-)
white flashing lines on screen macos 10.12.4
