'p' key is somehow mapped to 'mute'

Try restoring defaults in keyboard preferences.

This sounds disturbingly familiar to a problem I have.

My late model 2009 mbp's hard drive was failing, causing all sorts of I/O errors, including random key events and remappings. I put in a new hard drive and reinstalled from scratch, and transferred NOTHING to the new install. the I/O events have stopped triggering wildly, but the remappings stayed. For me, the following keys all trigger the mute button:

0 - p \ ; / <enter>

Since the problem survived an os reinstall, that suggests it is a hardware issue rather than a software one.

Playing with an arduino should not have affected anything. Not saying it didn't, but it shouldn't have. Whatever firmware that exists that handles the keyboard is more or less untouchable.

Binarian

This issue is haunting me for the past 3 weeks, did you get any answer to that? did you solve it?

BTW - If I hit the mute key it acually outputs 'p' as well.

Please help (it is almost impossible to write w/o using 'p'...)

Unfortunately, no. I ended up getting a new laptop (it was time for an upgrade anyway). I took the old one to a non-apple repair store in NYC and they repaired it pretty well. Only one or two extra keys trigger the mute key now, which is an improvement over the entire right half of the keyboard. In any case, I have turned down the volume al the way, and don't use that machine for anything involving audio.

I know it *****, but if you can afford a new machine, it's not a terrible way to go. You can still use the old one for research purposes or something. A second monitor is great for most applications, but a second machine altogether, I have found, is even better.

Binarian

I bought it 13 months ago, I was hoping this is not a hardware problem, but it looks like yours was.

The only solution I found was to have the function keys work as regular function keys (mute=f10) and to map f10 to nothing. I'll stick to that for now.

Thanks for the relpy

I had exactly the same problem today, oddly with the same keys.

Do you know what worked for me?

The goodn´old BLOW 😁

I gave a very strong blow over the problematic keys - in special the F10 key, which I could see was triggering by itself and very sensitive. One might try to take the keys off and clean instead.

Anyone could try that and give a feedback to see if it worked too?

Pressing really hard on the problem keys helped me. It's definitely a piece of dust or crud that gets knocked loose that causes this behavior with the volume buttons.

I have removed, cleaned, and reinstalled the keyboard. That fixed the problem for a few weeks. But the crud must still be in there because the problem came back. That's when I tried blowing and pressing.

Genius! Solved the problem instantly. I can't take my keyboard apart so I just banged it and lots of crumbs fell out. Very helpful thank you so much:)