Both the 13” & 15” unibody systems have issues with the HD SATA cables. The first generations did not support SATA III (6.0 Gb/s) I/O. The original Apple drives where SATA II (3.0 Gb/s) so they never pushed the limits of the cable. Even some SATA III drives 5200 RPM drives still didn’t push the limits of the cable, but SSD’s do!
In addition, the thin foil wires within the cable can breakdown. This is when people over bend the cable trying to crease them instead of making even smooth arcs.
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So the fist thing is to replace the HD SATA cable with the newer version. For the 15” [product|IF161-100-2] and for the 13” [product|IF163-041-2] And yes! These are for the 2012 models and are fully workable in the 2011 models.
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So the first thing is to replace the HD SATA cable with the newer version. For the 15” [product|IF161-100-2] and for the 13” [product|IF163-041-2] And yes! These are for the 2012 models and are fully workable in the 2011 models.
In addition to the new cable you’ll want to place a strip of electricians tape on the uppercase where the cable crosses over as the rough surface can also wear the cable. On the 15” models you need to make sure the plastic bottom lid mid plane clip near the drive is not broken as the pressure of the bottom case can cut into the cable where it crosses over the optical drive.
Once you have replace the cable we now have the second issue:
When you upgraded to High Sierra the OS installer updated the drive from HFS+ to APFS and the systems firmware was also updated. On your 13” system which you’ve already upgraded to Mojave it too would have upgraded the SSD to APFS but the 2nd version and as far as I’ve found the system won’t read High Sierra APFS SATA drives.
As for fixing things: I would put the drive back into your 15” and using the recovery partition run Disk Utility to see if you can at least get the drive running so you can recovery anything important. Once you’ve done that reformat the drive and re-install the OS. You might want to redo the full drive using an external bootable USB OS installer drive [https://www.macworld.com/article/3092900/macs/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive]
Frankly, I don’t recommend running High Sierra or Mojave on SATA based systems as Apple has not addressed the queuing issues which could have been the root issue in your case.
I don’t think your drive is dead!
Both the 13” & 15” unibody systems have issues with the HD SATA cables. The first generations did not support SATA III (6.0 Gb/s) I/O. The original Apple drives where SATA II (3.0 Gb/s) so they never pushed the limits of the cable. Even some SATA III drives 5200 RPM drives still didn’t push the limits of the cable, but SSD’s do!
In addition, the thin foil wires within the cable can breakdown. This is when people over bend the cable trying to crease them instead of making even smooth arcs.
So the fist thing is to replace the HD SATA cable with the newer version. For the 15” [product|IF161-100-2] and for the 13” [product|IF163-041-2] And yes! These are for the 2012 models and are fully workable in the 2011 models.
In addition to the new cable you’ll want to place a strip of electricians tape on the uppercase where the cable crosses over as the rough surface can also wear the cable. On the 15” models you need to make sure the plastic bottom lid mid plane clip near the drive is not broken as the pressure of the bottom case can cut into the cable where it crosses over the optical drive.
Once you have replace the cable we now have the second issue:
When you upgraded to High Sierra the OS installer updated the drive from HFS+ to APFS and the systems firmware was also updated. On your 13” system which you’ve already upgraded to Mojave it too would have upgraded the SSD to APFS but the 2nd version and as far as I’ve found the system won’t read High Sierra APFS SATA drives.
As for fixing things: I would put the drive back into your 15” and using the recovery partition run Disk Utility to see if you can at least get the drive running so you can recovery anything important. Once you’ve done that reformat the drive and re-install the OS. You might want to redo the full drive using an external bootable USB OS installer drive [https://www.macworld.com/article/3092900/macs/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive]
Frankly, I don’t recommend running High Sierra or Mojave on SATA based systems as Apple has not addressed the queuing issues which could have been the root issue in your case.