I experience for the second time now a problem with the keyboard of my MBP 15" 2011 (8,2). First time was in 2013. exactly 3 days after expiring of warranty, these keys failed - first intermittently, than soon after completely. Did cost me a lot of money at that time to get it repaired (it was one of the official apple service partner - told me they replaced it). Now, again nearly exactly 2 years later, this problem begins again with exactly the same symptoms. I took off the keys hoping cleaning could help. But the space under the keys was nearly perfectly clean. After the "Cleaning" action, the keys worked again (the MBP was cooled down during that time). For 20 minutes I was happy - but the more I was using the MBP again in the hour after all this , the more the keys failed again. Now I have a thesis: every time the MBP gets really warm/hot, the soldering or material itself of the keyboard risks to get less efficient (same problem as he dGPU-Problem with theses models ?) and the keys just above the CPU begin to fail (at least intermittently). The line from key T to O is EXACTLY on top of the CPU (at least, the hottest part of the downside is exactly underneath these keys), and I think this might be the problem. In my case, this is already beginning BEFORE the MBP even starts active cooling and without power-using. Are there other users with similar problems? After a short search I found this similar posting which might confirm a little bit my thesis: The fact that there are people who make their money with nothing but keyboard-repairs on MBP seems to indicate that there is a market - and therefore perhaps an issue… I use Nootebooks since 1994 (IBM, Toshiba, Panasonic) and NEVER EVER had any problems with the keyboard - this began with the MBP…. even for the second time now..