I'm running macOS 10.12 on a MacBook Pro (Retina, 13-inch, Early 2015).

Randomly, mouse keys was enabled when my hands were not touching the keyboard. I don't have a bluetooth keyboard (although I do have a bluetooth mouse which I was not using at the time). This is the second time it has happened.

This is either a software or hardware bug, but it seems oddly specific to be a hardware bug when I don't see other random keypresses.

  1. How can I diagnose this? I can't find any mention of 'mouse' in system.log.
  2. Is this a known bug? I can't seem to find any other mentions.
  3. Can I prevent this from happening again?

1 Answer 1


Default trigger switch for Mouse Keys is to hit Opt ⌥ 5 times.

You will usually hear the little 'zipper' noise it makes as it switches.

Occasionally, you can trigger it accidentally with seemingly unrelated presses of Opt ⌥ . To reverse it, just tap it 5 times again.

To disable it entirely, System Prefs > Accessibility > Mouse & Trackpad > Options... & uncheck

enter image description here

  • Thanks, but as I said, I didn't touch the keyboard. I have unchecked this box however, and I'll see if it happens again!
    – Joe
    Oct 11, 2016 at 12:16

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