Pressing a key that doesn't do anything, sheds a blue light on the screen for a moment, and it's quite annoying.

For example, in iTerm, since pressing Down Arrow Key doesn't do anything, so it sheds blue light on the screen to let me know there is something with what I'm doing, but it's pretty annoying.

I use Vim for development, and time and again, I press Esc to switch between different modes, and this thing annoys a lot. Is there a way to get rid of it?

  • Have a look at System Prefs > Accessibility > Audio. Do you have Flash Screen activated? [You can test to see if it looks the same with the test button on there]
    – Tetsujin
    Aug 24, 2016 at 7:40
  • No, it's deactivated form here, but it's pretty much the same thing.
    – Arslan Ali
    Aug 24, 2016 at 7:44
  • I'm not sure it it's still an option anywhere, but the Mac used to flash the screen if the system volume was turned to zero/muted.
    – Tetsujin
    Aug 24, 2016 at 7:45
  • Does the same flashing happen with Terminal?
    – dan
    Aug 25, 2016 at 7:48
  • @danielAzuelos Yes. Everywhere, including Teminal app.
    – Arslan Ali
    Aug 25, 2016 at 10:07

1 Answer 1


Still have no idea what's wrong with it, but searching on Google gave me the following command to execute, and it did the job:

sudo killall coreaudiod
  • Google sold you as popular as stupid a piece of advice.
    – dan
    Aug 24, 2016 at 8:02
  • @danielAzuelos Kindly explain if I had something wrong.
    – Arslan Ali
    Aug 24, 2016 at 8:08
  • Is it OK after a restart of OSX?
    – dan
    Aug 25, 2016 at 7:50
  • Restarted my mac after that, and it is working OK. No issues.
    – Arslan Ali
    Nov 7, 2016 at 1:19

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