Spindown / Disable internal unused iMac HDD

[raab90]

I have a 2012 work iMac that I currently use with an external SSD as the boot drive for speed. The internal drive I believe is on the way out as its clicking and whirring a lot, I'm not bothered about any further damage to the drive as I have the SSD running my OS. BUT its a super annoying noise that's always there and I wondered if there's a way, without taking the iMac apart, to spin down the HDD or disable it so it doesn't click and whir. I have already tried to unmount and eject the disk in Disk Utility but the noise still occurs so it sounds like power is still going to the HDD. Any suggestions?
Thanks

 

[Fishrrman]

Here's a quick-n-dirty suggestion that just might do the job for you.

Use disk utility to ERASE the internal drive, so that it's empty.
Then... just "leave it alone", in-place and untouched.

There's a free little menubar utility called "Semulov" that you can use that will dismount the drive once the computer is booted. Give this a try. You can find Semulov here:

kainjow

You will still have to dismount the drive after a reboot, but it takes only a second.
And you won't have to pry open the Mac (with the risks that entails).