mac pro middle 2012 not finding harddrive

Make sure to turn off the EFI Firmware Password as that will make it easier to work on the laptop.

If you have issues navigating Recovery Mode using the built-in keyboard and trackpad, then try using an external USB keyboard & mouse.

If you have issues with the internal drive, then you may need to replace the hard drive SATA cable. On the 13" non-Retina model this cable has an extremely high rate of failure.

Does the laptop have the original Apple memory or does it have a third party memory upgrade? Maybe there is a memory issue as well.

Try running the Apple Diagnostics.

peter354 wrote:

hi thanks for your help

have ben plodding through rebuilding the computor ,and have come to the same conclusion that there is more than just a hard drive problem.so have ordered a new hard drive cable ,Have manage to revive the old hard drive by using another external hdd

now trying to up date it to a more modern OS something like high seraria as a lot of the software will not run on the the 10.7 that's is installed

If you are using used drives, then perhaps they are also bad or worn out (a worn out drive can be just as problematic as a drive with bad blocks). You can run DriveDx to check the health of a hard drive. Feel free to post the report here using the "Additional Text" icon which looks like a piece of paper.

If you have access to another compatible Mac, then you can create a bootable macOS USB drive (start with macOS 10.11 as it may be needed before being able to install a later OS):

https://support.apple.com/en-us/HT201372

Not sure how to turn off the EFI Firmware Password to make it easier to work on the laptop. as it still occosanaly still default to the rebuild by wireless screen , and still trying to find how to update the SO as it insistes on rebuilding on rescue screen to down loading the existing 10.7

Here is how you disable the firmware password:

https://support.apple.com/en-us/HT204455#turnoff

The laptop does have USB3 ports, but if your adapter is USB2 only, then it will definitely slow things down. Plus a hard drive will be slow anyway. An SSD can give the laptop a nice performance upgrade even when used with an external USB3 adapter.

Keep us updated on the progress.

Good luck.

peter354 wrote:

As for some reason the hard drives I have will not take a update to sierra , comes up with the error (firmware doesn't have a suitable partition)

macOS requires a properly partitioned and formatted internal drive in order to install macOS 10.13+ as the installer performs a system firmware update which requires the use of the internal drive. The internal drive can be empty, but the internal drive needs to have a GUID partition and MacOS Extended (Journaled) file system.

.all i have to do is work out how to replace the hdd cable as the small separate end seems to be stuck to the casing

peter

The cable is stuck to the case with some adhesive. Just gently pull the cable maybe even using the flat edge of a nylon stick (spudger) to help lift the cable.