mid 2012 macbook pro - row of keys not working

I can suggest this is a hardware problem and you need to replace the upper case/keyboard assembly.

Woodpig wrote:

The third row of keys (ASDF etc) on my Macbook Pro has stopped working - or rather, only works intermittently and partially. I've had this problem for a while now, and it's persisted through various OS (currently running Sierra 10.12.1).

Thanks for your reply. Is there any way to verify that this is indeed a hardware issue? Do you know what replacing the upper case/keyboard would involve?

You painted a clear picture, intermittent, partial, various OS upgraded.

The keyboard is part of a upper case replacement. Not for the light hearted—everything has to come out and be reassembled. You can see how-to videos https://www.ifixit.com/Store/Parts/MacBook-Pro-15-Inch-Unibody-Early-2011-throug h-Mid-2012-Upper-Case/IF161-075

Look especially for the vendor http://www.PowerbookMedic.com. Many time PowerbookMedic will be sold out on their website as well but available via Amazon or eBay.

I can say that In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test

Genius reservation http://www.apple.com/retail/geniusbar/

on-line https://getsupport.apple.com/GetproductgroupList.action

check warranty https://selfsolve.apple.com/agreementWarrantyDynamic.do