Released June 2012, Model A1278. Intel processor with Turbo Boost, Up to 512 MB DDR5 Video RAM

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Questions on installing SSD and drive cables

I have a MacBook Pro 13 inch, mid 2012

  • 2.5 GHz Core i5
  • 7 series chipset

I want to install a new 512 GB Samsung 850 PRO SSD which I bought.

I tried many times to replace it to my current HD but the SSD is never detected by the system.

So I thought the SSD was damaged but I got it checked by the seller and they said is not.

I put back my old HD instead and it is working fine. Would you say then it is related to the cable?

I already replaced the flex cable not long ago with a NEW HDD Hard Drive Cable 821-2049-A for Apple MacBook Pro 13" A1278 2012 ...

Thank you for attention

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You installed the older cable! I would install the newer version MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable - Apple P/N 923-0104.

I would start there.

Update (02/20/2018)

What did you connect your new SSD into? A MS Windows system, or, a Mac to test it.

Lets try connecting the SSD externally using a SATA to USB connection to a working Mac System so we can prep the drive externally. Here's one adapter: Startech 2.5" SATA to USB adapter

Here's a good reference to prep the drive: [|Format an External Hard Drive or USB Flash Drive for Mac OS X]. We want to make sure there is only one partition on the drive and that needs to be GUID/MAC OS Extended Journaled.

If you have a friend with a Mac have hime help you create a USB OS Installer drive. I would recommend sticking with MacOS Sierra with a SATA SSD Apple still has some issues with queueing which I'm hoping will be fixed soon. Here's a good write up to walk you though it: How to create a bootable macOS Sierra installer drive.

Now plugging both the new SSD and the OS installer to your system you should be able to see and install the OS onto your new SSD. Make sure you it boots up on its own and then plug it back in internally. You should be working now. If not you might have a bad cable or damaged it some how.

MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable Image


MacBook Pro 13" Unibody (Mid 2012) Hard Drive Cable


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Dear Dan, after some weeks I got chance to test the proposed configuration. This took some time because, after receiving the Mac Book Pro 13" Unibody mid 2012 from iFixit, I wanted to make sure the SSD is ok. And it is, while the system does not detect the SSD.

Could you Dan please let me know if anyone else has had the same issue with a Mac Book Pro 13" mid 2012 + Samsung SSD 850 PRO ?

Thanks a lot for any suggestion you might have for me!


I have a 15" & a 13" both have Samsung SSD's. All I've ever installed which is somewhere north of a 100 systems is Samsung SSD's. So I think its safe to say the SSD is not likely the issue ;-}


SSD was tested by the shop I bought it from on a MS Windows.

I created a bootable MacOS on a USB pendrive (and this volume is detected by disk utility).

I currently do not have in my hands a USB to sata, I am gonna get one and prepare the SSD externally on my mac first.

Thanks a lot for attention and time, will let you know!




@kant84 - What they likely did was make the drive FAT or NTFS so the structure of the drive is not compatible for a bootable MacOS partition (GUID). So you need to make sure nothing is on the drive so the drive can be setup with GUID.


Dear Dan I found out the SSD with no partition is not detected by my MacBook Pro 13 inch, mid 2012, 2.5 GHz Core i5, 7 series chipset. The SSD has to be initialised before a mac could detect it.

So I used a windows machine and through an external SATA to USB adapter, initialised the SSD to an exFAT. Then my Mac could see it and I could format it to a GUID partition.

The internal flex cable had nothing to do with it in my case, I am still using my former one, not the one I bought at iFixit! :)

Currently W/R operations are x50 to x200 faster than with my old HD!

thanks a lot for your numerous feedbacks


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