I have recently upgraded to SSD (Samsung Evo 850) from HDD on my MacBook Pro Mid-2012.

However, the installation of SSD has been very painful. I tried to use Disk Utility in recover mode many times but it would fail either to erase or mount the SSD, even though it recognized that the SSD was plugged in. I thought it was the faulty SSD.

Then I hooked up the SSD using USB and proceeded to install OS X on it (using my HDD). The SSD functioned very well using the USB, so I put it in, and hooked up using the flex cable that was previously used for my HDD. However, it doesn't function, the OS sees that there is a drive hooked up, sees the name, size and etc, but won't load, gives me the question mark folder sign, when I try to verify or repair the disk, it fails to do so.

So I think it is something with the SATA cable. But the cable functions perfectly when used with the HDD. So I was wondering if the HDD cable that comes with MacBook Pro Mid-2012 is compatible with SSD. I have watched several videos of people upgrade from HDD to SSD, but they all seem to be using the same cable. Any ideas what might be the issue or if I need a different kind of cable?

EDIT: The issue has been solved. As people have suggested here, it was just a faulty cable, or just the original cables don't work with SSD. I bought the same cable, 821-1480-A from a vendor on Amazon and it works quite well with SSD for now. Thanks everyone for your help.

  • Could you post the model of your HDD. This will allow me to check if the drive is a SATA II or SATA III drive. Also, what is the screen size of your MacBook Pro and does it have a Retina display? This will help in determining whether your Macs identifier is either MacBookPro9,1, MacBookPro9,2 or MacBookPro10,1. Commented Aug 1, 2016 at 20:55
  • It's a non-retina, Mid-2012 Macbook Pro9,2, 13". I don't know exact model of HDD, but I tried with two HDDs, both Samsung that came originally with the Macbook.
    – Kaladin
    Commented Aug 2, 2016 at 21:10
  • I'm having the exact same issue. Mid-2012 13" - MD101LL/A* - MacBookPro9,2 - A1278 - 2554* Put in new SSD and it is recognized but boots to "0" symbol. Also tried to select it in Startup Disk and it says the drive is not Blessed. Old HDD works fine but not any SSD that I've tried. Both SSD's boot fine in a 2015 and 2011 Macbook Pro. I'm going to switch out the cable.
    – iheartmacs
    Commented Nov 20, 2017 at 21:13

1 Answer 1


I have read where the logic board is capable of working with SATA III drives which allows for the installation of either a HDD or SSD. When a Mac is sold with a HDD, usually this is a SATA II drive. Therefore, the cable used is designed for this type of drive. The cable can not be used with SATA III drives. When sold with a SSD, this is a SATA III drive. In this case, the cable used is designed for a either a SATA II or SATA III drive.

The end result is that if you started with a HDD, then a upgrading to a SSD may require a different cable.

  • This was my thought exactly except for I cannot find any other type of cable that goes with this macbook. There is only one, 821-1480-A. I am trying to figure out whether I am on SATA II or SATA III, it says "Link Speed: 6GB; Negotiated Link Speed: 3 GB." So I think it actually is SATA III that came originally with the mac
    – Kaladin
    Commented Aug 2, 2016 at 21:13
  • If you figured out where to find the Link Speed, then you should also be able to find the HDD model number. This number is given below the Link Speed in the System Report. Anyway, your above comment tells me the HDD is a SATA II drive. The actual internal transfer rate of a HDD is slower than both SATA II (3 Gb/s) and SATA III (6 Gb/s) external transfer speeds. Apple normally ships Macs with SATA II HDD. A SSD should be a SATA III drive and have both a Negotiated Link Speed of SATA III (6 Gb/s). Commented Aug 2, 2016 at 21:49

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