After having cleaned my mac with some antistatic foam product, weird keyboard problems started happening:

with keyboard viewer, pressing CTRL does not enable CTRL, however if I press LEFT SHIFT, it enables BOTH SHIFT KEYS AND CTRL. This quite a handicap because I use modifier keys regularly.

(I did reset the SMC and the PRAM, noticing that the combo SHIFT-CTRL-ALT-POWERBUTTON (PRAM combo) works, which makes me think the issue is at the software level, not hardware.)

thanks for your answers :)

  • Damp microfibre cloth, nothing else, or you get wet stuff in the circuitry. You could hope it dries out. Shift/Ctrl/Alt/Power doesn't eliminate it being hardware
    – Tetsujin
    Apr 9, 2015 at 14:00
  • use hair dryer and hope for the best
    – Ruskes
    Apr 9, 2015 at 16:45

1 Answer 1


If the product you used to clean the keyboard was wet, you could have created a short in the keyboard or perhaps even corroded the contacts under the Control key.

Two outcomes:

  1. You give it a few days to dry out.
  2. You buy a new keyboard.

Hopefully #1 will take care of it for you!

In the past, I've scrubbed nasty, dirty keyboards with a firm brush and water under a bathtub faucet and then let the keyboard dry out for a week. However, that was not the low-profile "laptop like" keyboard that Apple has been providing for the last decade, so I can't say that I've done it on modern Mac keyboards. But that all being said, the key thing is that clean water (NO SOAP!) should leave no residue (unless your water is very hard) and as long as you don't introduce electricity into the mix while it is still wet, you shouldn't be risking creating permanent short circuit damage.

  • I used a little rubbing alcohol on a q-tip, to get a bit of the alcohol under some sticky keys (ok, food spill) and tapped them a few times... it cleaned and then evaporated. Previously, when left-control stopped working and still had Applecare - they replace keyboard.
    – Zo219
    Apr 10, 2015 at 2:02

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