Boot MacOS on external disk - default

Discussion in 'Mac Basics and Help' started by Demovx, Jan 3, 2018.

  1. Demovx macrumors member

    May 12, 2015
    I have a qestion.

    I have iMac with usb external disk with MacOS High Sierra. ( No APFS ).
    When i power up imac, i see black screen. After 10 seconds, the apple logo appears and the booting from the external usb disk. All works fine but i need boot default from external USB ( save the 10 seconds ;p )

    My internal disk is clean - no MacOS On this drive.

    Can i change in terminal or other app this setting?

    In my settings> start disk> i have only my external disk. ( MacintoshHD macOS 10.13.2).
  2. Fishrrman macrumors G5


    Feb 20, 2009
    Try going back to the startup disk preference pane and re-designating your external drive as the "boot drive".

    I will guess that a "short delay" after you press the power-on button is going to be "the norm".
    The iMac first has to check itself for hardware integrity, and then "poll the buses" to find the external boot drive. And then... start booting from it.

    I've been booting and running my 2012 Mac Mini from an external drive for 5 years now.
    Works fine...
  3. Demovx thread starter macrumors member

    May 12, 2015
    Hmm, if it's Ok and normal loading external disk 5-10 seconds that's Ok.

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