Factory installed 10.11 downgrade

Discussion in 'OS X El Capitan (10.11)' started by surfit, Nov 3, 2015.

  1. surfit macrumors newbie

    Joined:
    Nov 3, 2015
    #1
    We got several new iMacs this past Friday (10/31) which all came with not what was ordered, instead with 10.11. Have done everything including destroying the Fusion drive and recreating it so that no possibility of 10.11 exists on either the SSD and HD. Still the machine will not except Yosemite or any other OS older than 10.11. Even after CCCing 10.10 to the rebuilt Fusion, still will not accept the OS. Called Apple and they said once its been factory installed you cannot go back.

    Must be a way around this.....................

    Any input would be appreciated.
     
  2. Morpheo macrumors 65816

    Morpheo

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    Feb 26, 2014
    Location:
    Paris/Montreal
    #2
    May I ask why you'd want to install 10.10 on these?
     
  3. Ebenezum macrumors 6502a

    Joined:
    Mar 31, 2015
    #3
    If you are desperate you might be able to use Pike´s Macosxbootloader to install 10.10.

    I tried to downgrade Mac Mini 2014 from 10.10 to 10.9 some months ago without success, either I misunderstood instructions or it didn't work for technical reasons.

    Maybe you have better luck than I did.
     
  4. chrfr macrumors 603

    Joined:
    Jul 11, 2009
    #4
    If they are 2015 iMacs, you'll need to use 10.11; there's no way they can run 10.10.x.
     
  5. Morpheo macrumors 65816

    Morpheo

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    Paris/Montreal
    #5
    As mentioned on Pike's page his bootloader is for unsupported models of MacPros and Macbook Pros. OP has iMacs...
     
  6. surfit thread starter macrumors newbie

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    Nov 3, 2015
    #6
    In an enterprise environment we don't want to introduce an OS that is so new. There are still many unknowns about 10.11 and many issues are still showing up. We don't want 10.11 and its issues until they have been resolved. Yosemite works fine with AD and all our other Macs are running on 10.10.
     
  7. chrfr macrumors 603

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    Jul 11, 2009
    #7
    It's time for your organization to rethink how it handles hardware purchases and OS deployment. You won't be using these iMacs with 10.10.x.
    Apple has made El Capitan available for testing for several months; either your organization needs to be sure that 10.11 works and test while it's still in beta, or the company needs to make sure it buys enough old hardware that can still run the now discontinued operating system to cover future needs.
     
  8. 9fiftyfive macrumors member

    9fiftyfive

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    Oct 26, 2015
    #8
    Put it in to internet recovery mode, and from there you can delete your entire disk's partition. After that, open up "Install OS X", which will prompt you with an installer. The installer will then download the original OS those iMacs came with. You can then re-download Yosemite via the Mac App Store and install it on each computer. Good Luck!
     
  9. Erdbeertorte, Nov 3, 2015
    Last edited: Nov 3, 2015

    Erdbeertorte macrumors demi-goddess

    Erdbeertorte

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    Castle Grayskull, Eternia
    #9
    If these are the new 27" 5k iMacs with Skylake chipset, I can assure you that you can't even boot the normal build of El Capitan 10.11.0. You have to use the preinstalled version or update to 10.11.1, what you also get by internet recovery now.

    I don't know if the Late 2015 4k iMacs can run Yosemite, but they also got a different build of El Capitan.
     
  10. lssmit02 macrumors 6502

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    Mar 25, 2004
    #10
    My understanding is that Apple locks all new Macs to the currently shipping OS.
     
  11. chrfr macrumors 603

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    Jul 11, 2009
    #11
    Apple doesn't provide support in older operating systems for newer hardware, but they don't lock any Mac to a given OS. The rule of thumb is that a given computer cannot install or run a version of the OS earlier than what was was installed when it was new. There are exceptions, in cases where a computer's lifespan crosses over several versions of OS X, but for a newly released computer like a 2015 iMac, 10.10.5 won't work.
     
  12. surfit thread starter macrumors newbie

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    Nov 3, 2015
    #12
    As I stated in my original post we did not order these with 10.11. At this point I'll go back to our purchase agent and see we get these swapped out. The rest of this thread pretty much summed up what I expected.
     
  13. hallux macrumors 68020

    hallux

    Joined:
    Apr 25, 2012
    #13
    It's not quite that simple. I work in an enterprise environment also, we also support Macs. The business has blocked installation of 10.11 until all security tools (Mcafee and Digital Guardian to name 2) have been updated by the vendor and then gone through a period of testing for compatibility in the environment. The 2 vendors I mentioned previously had committed to 90 days as their window to provide updated apps, the business committed to a period of 90 days after that for delivering the tools for upgrading the Macs in the environment. In our case, I don't think we support any Macs that wouldn't be supported by Yosemite.

    You don't get a choice what OS comes on Macs when you order from Apple (or an authorized Apple reseller). As was noted before, if you got the 2015 iMac there is simply no support for the hardware in versions prior to what shipped on it. Consider it similar to trying to install Windows 9x on a modern computer, the drivers just aren't there. Ok, that may be extreme compared to Apple not supporting new hardware on an OS that's only a year old but you get the picture.
     
  14. chrfr macrumors 603

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    Jul 11, 2009
    #14
    I too work in an enterprise environment supporting Macs and it really is that simple. Either you plan your hardware purchases based on your OS compatibility and buy extras of older, compatible models while they're still being sold, and well before they might possibly be discontinued or updated, or you get the new OS to work. Apple doesn't provide any other options; the model of calling up the Dell rep and ordering new workstations with a 1-or-2-versions-old OS doesn't apply here.
     
  15. surfit thread starter macrumors newbie

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    Nov 3, 2015
    #15
    Well, I'll let you two hash out your differences. I had asked for some simple input, not scripture..... out!
     
  16. Erdbeertorte macrumors demi-goddess

    Erdbeertorte

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    Castle Grayskull, Eternia
    #16
    You have to buy the Late 2014 iMac or older to use Yosemite. There is no other option. Apple directly doesn't sell them anymore, just some refurbished. But it depends on the country you are living. In my country there isn't a single 27-inch, but in the US online store there are a few:

    http://www.apple.com/shop/browse/home/specialdeals/mac/imac

    Maybe some authorized Apple resellers have more of them in stock, in new condition. I saw many of them in the first week of release.
     
  17. davidnayzar macrumors newbie

    davidnayzar

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    Jan 7, 2011
    Location:
    SF,California
    #17
    What about dump the EFI boot ROM and modify it? That is the only thing Apple uses to verify the system. It is not rocket science.
     
  18. chrfr macrumors 603

    Joined:
    Jul 11, 2009
    #18
    The reasons that older operating systems won't run on newer computers isn't a block in the ROM, but instead it's most often that there are no drivers for the newer hardware in the older operating system. The block is in the installer and that's not especially complex to modify, but it still won't run the computer.
     

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