When I press the left shift key a ± appears on the screen. It is a bit hit and miss, but for the most part it happens.

Googling I found this seems to be a common problem. The common recommendation is to reset the NVRAM and SRAM.

  • I did both of those things
  • It was recommended to try to reset the NVRAM several times so I did that
  • uninstalled my logic mouse driver (which uninstalled the related kernel extensions)

How can I get this fixed?

[EDIT] This is a 16" MBP. I am using a matias keyboard. It is a $100 keyboard from Fry's. Pretty high end; the action is really good.

[EDIT] I plugged in an old MS keybaord I had laying around. IT was working when I traded up to the new keyboard. IT throws garbage on the screen when I press the shift keys.

  • What kind of Mac are you running (and, if it is not a laptop, what kind of keyboard)?
    – nohillside
    Sep 10, 2020 at 19:32

3 Answers 3


Solved: For my Matias keyboard, the Mac combination for NumLock is simply the Clear key. Simply pressing the Clear key resolved the issue!

I have this same problem with a Matias keyboard. At first I thought the NumLock key was pressed, as there is no NumLock key on the keyboard. Funny thing is that my keyboard is Bluetooth and was connected to Windows 10. Both the Windows and Mac exhibited this same behavior.

Pressing Fn+n on the keyboard stopped the behavior on Windows, but not my Mac (as you can see from this post). The best part is that pressing Shift on my MacBook's built-in keyboard does not insert "±" !

Checked keyboard mappings and nothing seems to be set incorrectly. Reconnected my Bluetooth connection to a different key (keyboard has 4), and still have the same problem. I'll probably let the battery drain on my keyboard and see if that resets it.

Thanks to da4 for the keyboard mapping for the normal.

  • This worked for me with a different brand of keyboard. I wonder what caused the problem in the first place, though.
    – Vorticity
    Dec 27, 2021 at 16:22
  • I also have this issue with my Matias RGB Backlit Wired Aluminum Keyboard for Mac (FK318LS) suddenly today. I've only had it for 7 months. I tried pressing the clear key, but it does not fix the issue. I also tested on another Mac and the issue is there as well. I emailed Matias support and will see what they say.
    – petebocken
    Apr 24, 2023 at 20:01
  • Support said to blow some compressed air under/around the keys. That seems to have fixed it.
    – petebocken
    Apr 25, 2023 at 2:34

I went and bought a new keyboard and it works fine.

I had my friend plugin my broken keyboards and they have similar behavior on his Windows 10 PC (garbage on the shift keys).

I consider this solved but I am stumped that I have two keyboards with similar failure.

I would delete this question but there are other people reporting the ± on the left shift key too so I am just going to leave this question undeleted.


By default on macOS, typing ⌥ Option ⇧ Shift = (equal key not on an extended/numeric keyboard) results in the plus-minus sign (±). It seems likely that one of the keys being used as Option was stuck.

Since a second external keyboard also created unexpected results, it's possible that the stuck or malfunctioning Option key is on the laptop's internal keyboard.

  • I like the way you think, but I tried the keyboards on my friends windows computer and they did not work there either. I am chalking it up to a really strange coincidence. Sep 12, 2020 at 15:52
  • Not just the option key has to be stuck, also the = key, which seems most. unlikely. Sep 12, 2020 at 16:08

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