moutona10

Q: how to update OS X on an external drive

Background:
I have a computer that is running OS X 10.11.3 and the HDD drive is dying (let's call this drive A). 
I have another SSD drive which I used in the same computer 1 year prior (let's call this drive B).

I put drive B into the computer, however it will not boot, but instead the Prohibitory symbol appears.

I attempted to boot using OS X Recovery, however again, I landed on the  Prohibitory symbol.

Is it possible to update the OS X that is on my SSD drive B without first booting it in Recovery mode?

 

Question:

How to update the OS X on an external drive?

Posted on Jul 11, 2016 5:54 PM

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Q: how to update OS X on an external drive

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  • by leroydouglas,

    leroydouglas leroydouglas Jul 11, 2016 5:58 PM in response to moutona10
    Level 7 (23,520 points)
    Notebooks
    Jul 11, 2016 5:58 PM in response to moutona10

    You are not going to update your OS X on drive B until you can boot from it—that is your first problem to solve.

     

    Your SATA cable may be bad.

     

    Put the drive back in a external enclosure and boot from there as a test.

  • by theratter,

    theratter theratter Jul 11, 2016 6:07 PM in response to moutona10
    Level 4 (3,907 points)
    Desktops
    Jul 11, 2016 6:07 PM in response to moutona10

    If you can boot from Drive A, then boot from the Recovery HD on that disk. Clone the startup volume on Drive A to Drive B (SSD).

     

    Other solutions may be possible but not until we know exactly which model Mac you have and what version of OS X came pre-installed when it was originally purchased.

  • by Drew Reece,

    Drew Reece Drew Reece Jul 11, 2016 6:41 PM in response to moutona10
    Level 5 (7,537 points)
    Notebooks
    Jul 11, 2016 6:41 PM in response to moutona10

    Technically you can download & install OS X updates to a second HD via the command line. It is used in enterprise to build images for deployment using built in tools & some third party ones.

     

    I fail to see the point of doing that here though - you have an external disk that can't boot the Mac for whatever reason. I doubt this failure is because of an OS update, especially as you said the disk used to work in this Mac - assuming it still has the same OS installed.

     

    Personally I'd suggest you grab the OS X installer from the App store & build a USB Bootable installer. That way you have a 'get out of trouble' system that can repair, clone or install OS X that is independent to these 2 drives that appear to be flaky.

     

    Create a bootable installer for OS X - Apple Support

    Or use http://diskmakerx.com/

     

    P.S. give us a clue about what model of Mac it is to get appropriate help.

  • by moutona10,

    moutona10 moutona10 Jul 20, 2016 10:39 AM in response to theratter
    Level 1 (4 points)
    Mac OS X
    Jul 20, 2016 10:39 AM in response to theratter

    The mac in question is a 2008 MacBookPro.  I would rather not wipe Drive B (SSD) as it contains a fully functioning user account with applications etc.  Any suggestions would be appreciated.....

  • by leroydouglas,

    leroydouglas leroydouglas Jul 20, 2016 10:53 AM in response to moutona10
    Level 7 (23,520 points)
    Notebooks
    Jul 20, 2016 10:53 AM in response to moutona10

    moutona10 wrote:

     

    The mac in question is a 2008 MacBookPro.  I would rather not wipe Drive B (SSD) as it contains a fully functioning user account with applications etc.  Any suggestions would be appreciated.....

     

    No matter what you do, you should have a current backup plan in place. How to create a boot clone

  • by Drew Reece,

    Drew Reece Drew Reece Jul 20, 2016 1:03 PM in response to leroydouglas
    Level 5 (7,537 points)
    Notebooks
    Jul 20, 2016 1:03 PM in response to leroydouglas

    Can you please explain what steps you have tried so we are all on the same page.

     

    I don't think anyone has suggested you erase any disks. SATA cables are known to fail (or can be easily damaged) on some Mac laptops - isolating that is an important step.

     

    Also do you have an external drive case to fit one these disks into to try to boot externally? You can hold alt at power on (a.k.a option) to select other disks to startup from (assuming they are in working & bootable order). Does your internal disk show in this mode?

     

    Do you have access to another Mac to use to make a bootable USB stick from the OS X installer? That can be used to examine the disk that is fitted to the Mac. The installer contains tool to fix the Mac in addition to the actual installer, so you do not need to wipe the other drives, you just need a suitable spare USB disk (a 8GB or larger thumb drive is OK, larger & fast are better).

     

    It is also possible to backup if you have other Macs with the correct cables to connect them, depending on the state of your internal disk.