What could be causing MacBook keys to not work?

I have the same problem with a mac book air 2013 but there are more keys affected like C, O, E and R. Not all the time only every now and then.

I had the issue with the 'E' key several times. I tried restarting the computer, resetting VO, pressing the 'E" key many times and what finally worked was pressing the Control key. I hope it has gone away for good. :)

Hi,
This is either of two things. Either there is something with the software, or your keys that are not working actually aren't. Something could have gone wrong inside the key switches/the rubber part has broken, or the actual electronic components have failed. This can happen eventually on keyboards with extremely heavy use after a few years.

I agree that your keys may be wearing out after usual wear & tear. Or that something may be broken.

I have another reason thaj you should look into. How long has it been since you cleaned the keyboard? I mean like pulled off the keys & cleaned. If it's been a while, then I'd suggest if you can, pulling the keys off, & cleaning it where the keys go in the hole & the holes themselves. If you can pull the keys off, then get some canned air & sprayed it in there. If you can't, then still get the canned air & spray it on the keyboard. Dust & other assorted things & particles can get in & cause sticky keys. Or you can take it to a store & have them clean it if it makes you feel more comfortable. But try every so often to clean your keyboard! Hope this helps!

Go to the apple store, they will replace the top pannel for you.