Macbook Pro keys stop and start working sudenly

[Quantic1994]

I have Macbook Pro 13" late 2011 with Osx El Capitan every time i turn on my mac some keys don't work like ( A , 1 , F1 , Backspace ) i connect an external keyboard to type my user password after that i use my mac for about 30 minutes with external keyboard and the laptop keys suddenly start working again , what can this be i already tried SMC Reset and Pram. I also noticed that this happens every time i log off or shutdown my macbook.

 

[macmacmacr]

I have Macbook Pro 13" late 2011 with Osx El Capitan every time i turn on my mac some keys don't work like ( A , 1 , F1 , Backspace ) i connect an external keyboard to type my user password after that i use my mac for about 30 minutes with external keyboard and the laptop keys suddenly start working again , what can this be i already tried SMC Reset and Pram. I also noticed that this happens every time i log off or shutdown my macbook.

I have also noticed this same behavior on my MacBook Pro 13 running yosemite.

 

[duervo]

I have Macbook Pro 13" late 2011 with Osx El Capitan every time i turn on my mac some keys don't work like ( A , 1 , F1 , Backspace ) i connect an external keyboard to type my user password after that i use my mac for about 30 minutes with external keyboard and the laptop keys suddenly start working again , what can this be i already tried SMC Reset and Pram. I also noticed that this happens every time i log off or shutdown my macbook.

Boot it in safe mode (restart and hold down the shift key). If the problem still happens, then it's likely a hardware problem.

Considering it's a 2011 running 10.11, I would probably bet that a piece of third party software that worked in a previous OS X version, does not work properly in 10.11.