I have a 2012 MacBook Air and have been having some issues for the past few months. I wish I knew exactly what they were, but I'm lost on what it could be. First, it started with the computer freezing whenever transferring from an sd card via the sd card reader. Then I noticed the same issues when moving big/lots of files from anywhere to the computer hd. Then, just about a week ago, I was installing an update for 10.9 and it froze in the middle of the update. Left it for awhile but still wouldn't install. I proceeded to shut off the computer knowing that it could possibly screw everything. Well, it pretty much did. Though the hard drive would occasionally show up (via the OS X recovery utilities, or on the disk start up chooser after holding the option key). I tried resetting nvram, tried single user boot, but nothing worked. Eventually, I unplugged the computer, to reset the smc. Once I turned it back on, ssd was gone for good. So I ordered a new one from Other World Computing. Installed it, got Yosemite running and all seemed fine. Then last night and this morning, it started freezing within 10 minutes of use after booting. Turned it off and decided to reinstall the OS. Well, it wouldn't install now. I would get errors in different steps of the process. Then I tried installing Mavericks but same, errors at different steps of the process. Eventually, the SSD disappeared. But then it would reappear and after trying to install, I'd get an error that either the installation preparation failed or something failed during the installation. I'd try reboot and then the SSD would be gone! I'd shut everything down. Re-seated the SSD and then it showed up. But installation failed and it was gone again! I can't safe boot and I can't single user boot as the SSD isn't there. I can tell you that when I was able to single user boot or see the disk in disk utility, the verification of the disk would return NO errors. So does anyone have any ideas what the issue could be? I'm completely at a loss and have no idea what else I can do to get it back up and running. Could there be an issue with the motherboard? And could it be frying the SSD? Any help, suggestions, thoughts would be greatly appreciated!