The SSD had been working perfectly for about 14 months when suddenly my Macbook Pro (9,2) froze hard. I, too, had the same problem, but with an SSD from Other World Computing. Thank you in advance for your time and input. Reinstalled the old HDD internally (and put the SSD back in the USB dog house), re-started and everything works as advertised: Boot is ok from internal HDD, and it can see still the external SSD on the USB enclosure. Tried again with the SSD as internal SATA drive: NOTHING! I followed the procedure as outlined in other sites (iFixIt for example). I ordered through Amazon next-day and got it here. The common denominator seemed to be a faulty SATA cable assembly. I searched these forums and other sites for suggestions. The problem is consistent ONLY when the SSD is on the internal SATA connection. I went back and forth swapping the internal drive between the SSD and the original HDD. In any attempt there after it doesn't even show the internal SSD. While booted from the external USB (old HDD), I ran disk utility and the first time it displayed the internal SSD but it said it had ZERO space in it. I tried re-starting and booting from the old HDD now on the USB enclosure, which works, however it does not show the internal SSD as a bootable option (even though I could boot from aforementioned SSD while on the USB enclosure!) Once I try to turn the computer on, it will not recognize the now internal SSD connected to the SATA interface, and therefore cannot boot from there. This works well and Mac OS starts and runs no problem. restart the computer and boot from the SSD still on the USB enclosure (holding 'option' key during startup. put the SSD on a USB-SATA enclosure, carbon copy my existing HDD (including a recovery disk partition), formatted MAC OS Extended (Journaled) with a single GUID partition.

I've followed the most typical (in my opinion) preparation procedure:

I've purchased a samsung 840 Pro (512GB) SSD to install on my mid-2012 MacBook Pro running Mavericks (OSX 10.9.1) as a replacement for the factory 750GB (7200rpm) spinning drive.

Samsung ssd for macbook pro mid 2010