12-07-2013, 06:34 PM
I've been having all sorts of problems with my Late 2011, 17" MBP (running 10.7, then 10.8 and finally 10.9). Slow performance, even with 16GB of RAM, spinning beach balls, screen freezes, problems with iTunes and iPhoto and more. I've recently got back home after a five month cross country RV trek. In the last five months, I've made seven trips to six different Apple Stores. While in Texas, the motherboard was replaced to cure a bad USB port. Last week, an Apple Genius in the Walt Whitman Apple Store, Long Island, NY (in training no less) noticed that the serial number burned into the replacement motherboard did NOT match the serial number etched on the bottom. The motherboard thought it was in a MacBook Air! A second motherboard replacement fixed the mistake. I'm told this is incredibly rare as when a serial number is entered onto a motherboard, it must be typed in FOUR times and, can NOT be Copied and Pasted. "Diagnostics" had been run on my machine more times than I could count. I can't fathom how this went unnoticed for so long. Long story short; if you're experiencing any ongoing weirdness that can't seem to be explained, check that the serial number that is shown in "About this Mac" matches the serial number that is etched on the bottom of the case.