Can´t unmount original HD, after update to SSD

Discussion in 'iMac' started by Andre C., Oct 30, 2015.

  1. Andre C. macrumors newbie

    Oct 30, 2015
    Hello everyone.

    I hope you can give me a hand with a little issue I´m having.

    I have a late 2009 iMac 27" i7. I replaced the Superdrive with an 850 EVO SSD (boot drive). Everything is working great so far. Great speed improvement and I managed to keep my Superdrive in an external USB enclosure.

    I left my original HD in place, but would like to format it completely to store files, music, etc.

    Even though I´m booted from the SSD, I can´t seem to be able to unmount it and format it clean.

    Forcing the unmount in terminal doesn´t work either.

    I just want a clean, empty drive...

    Any ideas?..

    Thank you.
  2. fa8362, Oct 30, 2015
    Last edited: Oct 30, 2015

    fa8362 macrumors 65816

    Jul 7, 2008

    Perhaps I'm misunderstanding you ("unmount"), but why don't you just highlight the disc and erase it?
  3. Andre C. thread starter macrumors newbie

    Oct 30, 2015
    Hi fa8362

    I can´t do that because it has a Recovery Partition. This was the original boot volume of the iMac before the upgrade to an SSD. It can´t be unmounted.

    I actually managed to solve the issue by rebooting into the Recovery Partition and then using Disk Utility to format from there.

    Now I have my SSD (in place of the Superdrive) as the boot disk, and the original Macintosh HD as just an empty drive.

    I´m going to partition the drive so I have one partition as a backup to the SSD (via Carbon Copy Cloner), and the rest of the space to keep my files and music.


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