
Most SSD upgrades I've found for the 2012 MacBook Air consisted of an adapter that you plugged into the MacBook and to which you attached a standard M.2 connect SATA SSD. I tried one of these first and after a few weeks my Air wouldn't turn on at all. After reinstalling the original drive it worked again but I still needed the extra space. It was the best value I found with a proprietary native interface only used in the 2012 MacBook Air and it worked great :-)

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