ghenry1999
Level 1 (0 points)

Q: How do I wipe El Capitan off my I mac and load snow leopard from the disk?

How can I remove El Capitan OS and return to Snow Leopard if I have a Snow Leopard disk?

iMac, OS X El Capitan (10.11.2)

Posted on Dec 22, 2015 1:02 PM

by Niel,Apple recommended
Niel Niel
Level 10 (312,806 points)
Mac OS X
A:

Insert the DVD, restart with the C or Option key held down, use the Disk Utility on it to erase the internal drive, and install Snow Leopard.

 

(137478)

Posted on Dec 22, 2015 1:06 PM

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ghenry1999

Q: How do I wipe El Capitan off my I mac and load snow leopard from the disk?

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  • by Niel,Apple recommended

    Niel Niel Dec 22, 2015 1:06 PM in response to ghenry1999
    Level 10 (312,806 points)
    Mac OS X
    Dec 22, 2015 1:06 PM in response to ghenry1999

    Insert the DVD, restart with the C or Option key held down, use the Disk Utility on it to erase the internal drive, and install Snow Leopard.

     

    (137478)

  • by ghenry1999,

    ghenry1999 ghenry1999 Dec 22, 2015 1:28 PM in response to Niel
    Level 1 (0 points)
    Dec 22, 2015 1:28 PM in response to Niel

    Tried this and am now getting a black box that says Yoy need to restart your computer in 5 different languages.

  • by Allan Eckert,

    Allan Eckert Allan Eckert Dec 22, 2015 1:30 PM in response to ghenry1999
    Level 9 (53,621 points)
    Desktops
    Dec 22, 2015 1:30 PM in response to ghenry1999

    That is a kernel panic.

     

    They are usually caused by hardware problems.

     

    Why did you think you need to downgrade the operating system?

  • by ghenry1999,

    ghenry1999 ghenry1999 Dec 22, 2015 1:32 PM in response to Allan Eckert
    Level 1 (0 points)
    Dec 22, 2015 1:32 PM in response to Allan Eckert

    El Capitan OS in in conflict with my Nikon photo software and Snow Leopard was the only OS disk I could get ahold of.  El Capitan keeps blocking my attemp to downgrade.

  • by Allan Eckert,

    Allan Eckert Allan Eckert Dec 22, 2015 1:44 PM in response to ghenry1999
    Level 9 (53,621 points)
    Desktops
    Dec 22, 2015 1:44 PM in response to ghenry1999

    When El Capitan blocks the Nikon software is there any message provided as to why?

  • by ghenry1999,

    ghenry1999 ghenry1999 Dec 22, 2015 1:47 PM in response to Allan Eckert
    Level 1 (0 points)
    Dec 22, 2015 1:47 PM in response to Allan Eckert

    No, it just spins during the loading and does not boot up. Nikon says that it knows about the conflict, but recommends using an earlier OS.

     

    How can I get my Imac working again with this black box message coming up?

  • by ghenry1999,

    ghenry1999 ghenry1999 Dec 22, 2015 1:56 PM in response to ghenry1999
    Level 1 (0 points)
    Dec 22, 2015 1:56 PM in response to ghenry1999

    I now have El Capitan downloading from the wireless, which will at least get the computer running again.

  • by Mademoiselle Mac,

    Mademoiselle Mac Mademoiselle Mac Dec 30, 2015 8:18 PM in response to ghenry1999
    Level 1 (0 points)
    Dec 30, 2015 8:18 PM in response to ghenry1999

    There are SO many reasons to downgrade.

  • by Mademoiselle Mac,

    Mademoiselle Mac Mademoiselle Mac Dec 30, 2015 8:22 PM in response to Allan Eckert
    Level 1 (0 points)
    Dec 30, 2015 8:22 PM in response to Allan Eckert

    I do not seem to be able to boot from the SL disk either. Inserted disk, tried w/both C and option key - got silver screen w/apple in center and then - no farther... any Idea how to get beyond this point?? Thank you

  • by dcouzin,

    dcouzin dcouzin Jan 1, 2016 2:49 PM in response to Mademoiselle Mac
    Level 1 (10 points)
    Jan 1, 2016 2:49 PM in response to Mademoiselle Mac

    I don't know about the iMac but with my MacPro 5,1, the first thing I'd try is resetting PRAM.

    But in order to run an OSX installation DVD, I did recently have to remove all hard drives from the MacPro and put in just one drive that had been formatted using an earlier OSX.  The OSX install apps are fussy about the hard drive(s).  Drives that have been formatted in Lion or later can't be reformatted using earlier Disk Utilities.  Drives that have been formatted in Yosemite or later may be in a state of "core storage". This can be undone with a terminal insruction "diskutil coreStorage revert ...".  Sometimes it is necessary to remove a hard drive and thoroughly wipe it.

     

    A Mac's firmware can prevent running an OSX install app, but if the Mac ran that OSX before, and if it's firmware wasn't updated, the OSX install app can run, provided it finds a suitable drive.

     

    DC

     

    <Edited by Host>

  • by Lanny,

    Lanny Lanny Jan 1, 2016 10:01 PM in response to ghenry1999
    Level 5 (7,952 points)
    Desktops
    Jan 1, 2016 10:01 PM in response to ghenry1999

    In most cases, Macs won't be able to run older OS X versions than their shipping versions. What is your iMac model?

  • by dcouzin,

    dcouzin dcouzin Jan 2, 2016 7:02 AM in response to Lanny
    Level 1 (10 points)
    Jan 2, 2016 7:02 AM in response to Lanny

    The original post by ghenry1999 says "return to Snow Leopard".  Maybe this means Snow Leopard ran on that iMac, or maybe not.

     

    Perhaps I've been lucky in avoiding the "in most cases" in Lanny's rule-of thumb. My Mac Pro that shipped with Mountain Lion is running happily on Snow Leopard; my MacBook Pro (non-Retina) that shipped with Yosemite is running happily on Mountain Lion.  I think the firmware version is more critical than the OSX with which the Mac ships.

    DC

  • by Rachel Corey,

    Rachel Corey Rachel Corey Jan 26, 2016 6:33 PM in response to dcouzin
    Level 1 (105 points)
    Jan 26, 2016 6:33 PM in response to dcouzin

    I am on a MacBook Air,  A1370 Mid 2011.  I bought it as a back up for my Macbook Air A1370, because I need to stay with Snow Leopard (for a lot of reasons), if anything happened to my computer, even with a back up clone of the drive, Time Machine, it would not run on a newer logic board.  So I bought the same year and model as mine.

     

    The "new" one was loaded with El Capitain and I have been trying to wipe it and load my clone of my hard drive- but El Capitain is not letting me.  Same as OP.

     

    I have an external DVD drive, EC wont load the installer, it wont even see the drive when I hold down option and try to select a startup disk.

    It wont let me erase or format.

    So I used the back up of the EC drive (yes, I backed up first on a USB drive), it would allow it to be the startup disk, and from the backup USB drive of EC I was able to "erase" the El Capitain hard drive.

     

    But then when I tried to reboot and use the Snow Leopard DVD, or even the El Capitain USB drive, hold down option, it shows NO startup disk, I can only use "Internet Recovery".

     

    I had also tried holding down C at the start of this, trying to get it to install from the Snow Leopard dvd.  Holding down C then and now only brings me to an Apple logo.

     

    If its an A1370 logic board, it has to have shipped capable of running Snow Leopard, right?  Does El Capitain change the firmware on the logic board?  I will try resetting the PRAM...

  • by dcouzin,

    dcouzin dcouzin Jan 26, 2016 7:39 PM in response to Rachel Corey
    Level 1 (10 points)
    Jan 26, 2016 7:39 PM in response to Rachel Corey

    I don't think installing El Capitan changes the firmware, but whoever installed the El Capitan on the 2011 MacBook Air might also have changed the firmware.  Apple issued a 2015 update to that computer's EFI boot firmware. Boot into El Capitan and check System Information for the Boot ROM Version.  Compare this to the list in Apple's support page.

     

    If you must roll back your firmware to an earlier Snow Leopard tolerant version, how do you find the old installer and will it allow roll back?  Apple's "Firmware Restoration" CDs "cannot be used to return an Intel-based Macintosh computer's firmware to a previous version if a successful update has already been performed."  This puts you in hackland, or in search of a 2011 MacBook Air with its original firmware.

     

    DC

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