How to make mid 2012 Mini boot from USB 3.0 external HDD?

Discussion in 'Mac mini' started by davekro, Jun 21, 2016.

  1. davekro macrumors regular

    davekro

    Joined:
    Mar 31, 2011
    Location:
    No. Calif.
    #1
    I recall reading about this problem a while back but can't find anything via search right now. Can someone either point me to links where solution options for booting a mid 2012 Mini from an external HDD was discussed or describe what is needed? My ext. HDD is a 3 TB Seagate model SRD00F2 from Costco which only has USB 3.0 and no other options. If an adapter is needed, is there a recommended one that others have had success with?

    My OS (10.11.1) runs on the internal 500 GB SSD. I use the 1 GB internal HDD as my Time Machine backup drive. When I ran my late 2006 20" iMac, I used a USB 2.0 ext. HDD for my Carbon Copy Cloner bootable back ups. Now with my Mini and USB 3.0 ext. HDD, my bootable clones are not, well, bootable. :(

    Thanks,
    Dave
     
  2. Mr_Brightside_@ macrumors 68020

    Mr_Brightside_@

    Joined:
    Sep 23, 2005
    Location:
    The 6ix
    #2
    What happens when you boot up holding down option with the drive plugged in?
     
  3. davekro, Jun 21, 2016
    Last edited: Jun 21, 2016

    davekro thread starter macrumors regular

    davekro

    Joined:
    Mar 31, 2011
    Location:
    No. Calif.
    #3
    I only get the two internal drives showing as available. Mac HD (500gb SSD), MacHD-2 (1gb HDD Time Mach) and Recovery- 10.11.1.

    Upon booting with the Mac HD, of course I then see the six partitions of the external HDD.
     
  4. Mr_Brightside_@ macrumors 68020

    Mr_Brightside_@

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  5. davekro thread starter macrumors regular

    davekro

    Joined:
    Mar 31, 2011
    Location:
    No. Calif.
    #5
    Yes, I use Carbon Copy Cloner (Bombich) that does a daily incremental back up of my entire OS. Also, I cloned various versions of my OS during my transition from my old iMac. I like to make bootable clones before doing updates or software upgrades. That is why I have so many partions on the 3TB ext. HDD. I did not find out nothing from the ext. HDD was bootable for a while as I had not tried to boot from them.

    Are you (or anyone) able boot from an external USB 3.0 HDD on a mid 2012 Mini?
     
  6. DeltaMac macrumors 604

    DeltaMac

    Joined:
    Jul 30, 2003
    Location:
    Delaware
    #6
    I boot to a variety of devices - USB flash drive, USB 3.0 external, Firewire.

    If you boot to your normal system, then open System Preferences/Startup Disk - is your external USB drive listed as one of the choices for a startup disk?
    If not, then your backup to that disk is just not bootable.
    You COULD just boot to an El Capitan installer drive (this would be a handy time to have one - it is a simple task to download the El Capitan installer app from the App Store, then create a bootable USB flash drive using one of several different methods)
    So, boot the El Cap installer, and reinstall OS X, choosing the external drive as your destination for the install. You said you have multiple partitions, so select the partition that YOU want to use for booting.
    Let the installer continue.
    THAT will make it bootable again.
    And, you can choose your external as the default boot drive from the Startup Disk pane.
     
  7. davekro thread starter macrumors regular

    davekro

    Joined:
    Mar 31, 2011
    Location:
    No. Calif.
    #7
    Your comment jogged my memory that it might be an issue with the cloning software, so I Googled that.
    https://bombich.com/kb/ccc4/help-my-clone-wont-boot
    "...your Mac's firmware may have difficulty discovering the hardware that hosts your [CCC] backup."
    I will read through Bombich's troubleshooting steps. Thanks for the memory jog!
    I'll report back on what I find.

     
  8. davekro thread starter macrumors regular

    davekro

    Joined:
    Mar 31, 2011
    Location:
    No. Calif.
    #8
    Workaround found :)
    From the Bombich trouble shooting link:
    I started up w/ option key > no external volumes seen > unplugged/ replugged USB 3.0 cable to Mini > In 15 seconds my six volumes appeared! (+ 3 additional Recovery volumes) > I selected my main CCC incremental backup volume and it booted from it just fine! Sweet!:D

    I rarely need to boot from that external drive, so needing to do the extra step of un-replugging the USB cable is an easy work around. I am a happy camper. Not being real familiar with recovering from TimeMachine, I really like having a full second full system back up. Plus feels good having my entire OS on three independent drives, though two of those drives reside in the Mini.

    Thanks DeltaMac and Mr. Brightside for your helping me work towards a solution!

    Dave
     
  9. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #9
    My 2012 Mac Mini uses CCC to create a daily clone backup on a USB 3.0 hard disk. It boots fine over the USB 3.0 interface (I just tried it to be sure) using the option-key selection at boot. When you created the initial clone using CCC it should have created a bootable copy and also created a recovery partition (if your source contained one) after the initial clone operation.
     

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