Unable to erase Mac HD – “unable to delete the core storage logical volume” I'm trying to erase the my Mac Fusion Drive so I can sell it online. I have followed Apple's instructions on what to do, including erasing the volume, but to no avail. I always unmount, click "erase", but then it shows the error in the picture. After that, the volume disappears from the list of volumes, which is why you can't see it in the picture. To see it again, I need to restart the machine in recovery mode. 

I have no clue what is going on and I have never seen such an error before. If someone could help me out, that would be great. I don't want this machine to turn into an expensive paperweight. 



Note: Ignore the fact that the OS X Base system is highlighted, that is just what happens by default after the Mac HD disappears from the list of volumes.
Golden Rule:
you cannot trash the drive you're booted from. You need to be booted from another drive, even if it's a USB.