So I was attempting a thermal paste swap on my 15" rMBP, and everything was going fine until I began unscrewing the screws on the heat sink. They were a bit tough, and I had trouble with them, but I managed to unscrew them all but one. I kept trying to unscrew the screw that was troubling me but i just wouldn't budge, and upon further inspection it's clear that I've stripped it. After seeing that I stripped it, I began to think that I've messed it all up and I'm never going to be able to swap the thermal paste on my rMBP, which I really need to do, so I just screwed everything back together and closed it up. I'm still thinking this up to now, but I'm hoping I can find someone who could give me a solution. I really need to swap this thermal paste. Any input is appreciated.. thanks.