I have an old macbook pro (I think from 2013, but I am not sure), and the hard drive (WD blue 750gb WD7500BPVX, something like this) is broken (I think). Basically I can see it from the disk utility in recovery mode, but I cannot verify or repair it. I get some errors about it being write only, but the option to fix the permissions is greyed out. I think in order for the fix permission button to be enabled I need to mount the disk, but I just get and error when I try and mount it. I also cannot erase it (I get an error).
I have another hard drive (500gb Seagate ST95005620AS Momentus XT, something like this, from a windows laptop from around 2011), that as far as I know is working fine, and I want to put it into the macbook pro.
I connected the working hard drive to the macbook pro with an external usb novatech hard drive docking station, and was able to reinstall macOS on it. I was then able to boot the macbook pro to desktop with the hard drive still connected externally (over USB), and everything seemed fine.
I then took the bottom off the macbook pro, and swapped the hard drives (so that the working one is now plugged into the ribbon inside). However when I turned the macbook pro on it didn't recognise the hard drive at all. It couldn't even see it in recovery mode (literally not there at all).
What could the issue be? Why can it see and boot from the working hard drive when connect externally, but not internally?
I don't think that the SATA ribbon is broken, as the macbook pro can see the broken hard drive when it is plugged in internally.