Can't erase Mac Pro hard drive

[namonaip]

Hey guys,

I am rehabilitating a late 2012 15 inch Mac book Pro that my brother left in our basement. It wouldn't boot (stuck on apple logo for hours and hours) and for some reason I kept encountering an error while trying to reinstall OS X from the recovery partition. I have Sierra installed on an external drive so I booted from it. I was trying to format the internal drive and create the installation file from my external drive. I tried to format the internal drive using disk utility and also the terminal but I am encountering another problem with both of them. The process is stuck on "Waiting for partitions to activate". One time, i left the computer on no sleep for almost two days but still, nothing. I also tried a gparted live USB and thought of using a windows virtual machine to force format it but the drive wouldn't even show in both of those. Can't find that specific problem online either. Thanks in advance for the help.

 

[Audit13]

Possibly defective internal sata hard drive cable.

 

[Fishrrman]

Audit's suggestion is a good one. You might have that checked at an brick-n-mortar Apple Store (assuming there is one close enough).

My suggestion:
Take the internal drive OUT OF the MBPro, and then...
... using either a 2.5" USB enclosure, or a USB3/SATA dock, or a USB3/SATA dongle, connect it to another Mac and re-initialize it that way.

You might even install a clean copy of the OS that way, as well.

Insofar as an OS re-install goes, I've come to the conclusion that one of the easiest ways to do this, is to first create a bootable USB flash drive containing the OS installer of your choice. Utilities such as "Install Disk Creator" and "DiskMaker X" make this job easy. Or you can do it with the terminal.