Intermittent failure of certain keys to respond

Question

Came across the second MacBook Pro keyboard recently that exhibit very strange symptoms. Certain keys seem to stop responding despite being clean and traveling very easily just the rest of the keys. Both of them went to the Genius bar for testing, one of them for the 'long run', and came back as "works normally". Of course, despite still intermittently showing symptoms.

The affected keys in both cases were confined to the top row of letter characters on a qwerty-layout like tyuiop. Not always the same keys, not alway all keys. Sometimes all of them really do work normally.

Searching around there are some similar problems reported, apparently mostly on Apple hardware.

First port of call should be this Keyboard key stuck or not being recognized; how to fix but that reads like a permanent physical/electrical problem. And the supposed fix is really just an inconvenient workaround that further would be quite impractical to implement on that many keys.

Searching some more similar symptoms are reported here Keyboard Intermittently Non Responsive - Top row of Qwerty only (This issue was not really solved…)

qwerty row on macbook air won't work from time to time Also no solution but a lot of voodoo reasoning or observations.

shift key + qwerty row of keys not working To look at similar but non-fruity situation.

Keys qwer uiop Not Working, Rest Other keys Are Working Fine – Laptop, Desktop Linking the key failures to dirt.

Strange symptoms with strange solutions that indicate a keyboard for itself may be fine: Unresponsive Keyboard and Trackpad problem

Both keyboards I examined had no spill related damage, both were cleaned underneath the key caps (minimal dirt there before), one I disassembled completely to really clean it. There is no swollen battery, no strange matter inside the machines.

Two further peculiarities to observe: Pressing multiple (unresponsive) keys at once seems to yield a temporary relieve and the problems seem to be get more severe when the machine heats up and less severe when running cooler.

What could be the cause of this? How to fix it?

Answer 1

If you have this problem, prepare yourself for a long session of searches and partial answers. I wish Apple would summarize all the different possibilities in one page.

In my case, out went the "p" and then the ENTER key. (Survival trick: use the Keyboard Viewer to enter ENTER or any other key. If you are logged out I was not able to figure out how to enter "p" in my password using and ALT-### format ...).

So ... I did all the recommended resets (PRAM,SMC,safe mode reboot,upgrading to High Sierra). I checked that no System Settings were incorrect, added other language keyboards, upgraded to High Sierra.

Finally, I decided to risk going with the tools for the first time into my keyboard, removed and cleaned the "p" with help of this YouTube video, the best among many I saw. (Note not all keys are created equal and that several articles say the control keys —SPACE, ENTER, SHIFT, ALT, OPTION— are harder to put back in as they have a pin).

And ... nothing.

One article (which I cannot find now) had very useful pictures of the transparent film under the keys, which explains why keys that are in the same row tend to fail together. This film has gold conductive paint that follows a horizontal serial path on one side, so if there is corrosion or a mechanical problem in one key, it is likely to affect (or start affecting) keys in the same row, like when a bulb fails in a Christmas light with only two cables.

As the problem is intermittent, I discovered by chance that closing the lid, and putting the laptop vertically and putting pressure on both ends fixes the "p" and ENTER problems temporarily. I think my problem is the battery, which is 2-3 years old and at some point I've read that they start swelling.

Answer 2

Not a fix but this worked for me.

The fault was that the qwerty row was sometimes dead and would require a number of key presses to get the key to work. Once it worked then it would continue working until the system went to sleep and then same problem again.

For me, bringing up the British on screen keyboard and leaving it open in the Dock has kept the keys working faultlessly.

I have looked at many boards discussing this fault and all the 'experts' will not accept that it is a software fault and are telling all to fit new keyboards and io boards.

I hope this works for those who need a quick work-around.

Get it here:-

Go to System Preferences > Keyboard. Check the box that says "Show keyboard and emoji viewers in menu bar." Click the icon in the Menu Bar with the Command (⌘) symbol in it, and choose "Show Keyboard Viewer." The keyboard will show up on your screen. Then move it to Dock or keep it tucked out of the way bottom right of screen.

Answer 3

Ed Coombs' answer works for me too, not faultlessly though but much much better than without the keyboard viewer being 'live'.

If I had to guess, I would think that it is a hardware issue that has become a problem due to a software 'update' or program. The keyboard is 'polled' for input by the OS and where electromechanical 'tolerances' now fall outside the time allotted for 'responses' in the OS, the key press fails to be registered.

I suspect that OS changes in timings or anti-spyware programs trapping key presses might produce the unintended consequence of unrecognised key presses.

Adding the keyboard viewer clearly adds time as the viewer responds to keyboard presses - it may be that the OS takes the keyboard viewer key press rather than the keyboard input, so keyboard press > keyboard viewer > OS.

On the possibility that it is a 'timing' issue, before I found Ed's solution, my workaround was a more plodding deliberate style of typing - it worked but not well.

Answer 4

Solution

I've had this issue for years on my 2012 Macbook Pro that some keys on the right hand side of my Mac Pro keyboard would work on and off. Sometimes it would help to press them really hard, but sometimes they'd just be dead for days and then come back for no reason. The keys affected were = f12 [ ] right arrow and right command key, as well as all their shift functions. All the keys around them worked flawlessly. I just figured it must be a software issue, but I tried all the reset functions, restarting, etc. and the annoying thing is that it occasionally worked, but now I realize it was by chance, just from moving the laptop around.

Finally figured out today that it was caused by the rear panel putting pressure on the optical drive. If I shook the laptop so that the optical drive fell away from the keyboard a little, it would work again, and if I put pressure on the rear panel in a certain area with my knee it would stop working. When I opened it up there was a certain pressure point on the optical drive that would make it stop working, and it was very sensitive to any pressure in that area. I fiddled around for a while and finally found a place where I could wedge a paperclip under the optical drive so that if the rear cover was screwed on again it would put pressure on the other end of the paperclip and wedge the optical drive towards the rear panel away from the keyboard. It took a few trials to find the right spot, in my case between the hard drive and the optical drive. Also had to wedge in a staple on the opposite end to limit movement of the optical drive. I didn't have to remove the optical drive or anything. I unplugged the laptop from the power cord and took care not to touch anything electrical, but not sure if there's a shock risk - had to see what worked and what didn't though.

So far so good, I finally have all my keys back. But a bit annoyed that it was so simple. I don't know if it would be a similar thing for the left keys or not, but many people have noticed that certain pressure points have an effect, so I would guess that the cause is usually mechanical. The rear panel on my laptop is pretty soft and easily compresses the components, which seem to easily interfere with the keyboard.