Downgrading 2011 MBPs from Lion to Snow Leopard

Discussion in 'MacBook Pro' started by mrmister, Aug 2, 2011.

  1. mrmister macrumors regular

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    Dec 19, 2008
    #1
    Can it be done? Has anyone tried yet? I have been searching the web, and I see some theorizing, but I want to know if anyone has actually tried to do it.
     
  2. maflynn Moderator

    maflynn

    Staff Member

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    #2
    Sure, if you installed Lion yourself and the MBP came with SL, its easy. Pop the disc into the drive, reboot and proceed. Make sure your data is backed up though.

    If the MBP came delivered with Lion, then its a bit trickier. For the new 2011 MBAs it won't work, but since current MBPs already had SL on there you should be ok with installing SL.

    The issue is that generally the lowest version of OSX you can install on a Mac is the one that came on it. Since however there are no hardware changes on the MBPs you may be able to reinstall SL
     
  3. PenguinMac macrumors member

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    May 21, 2010
    #3
    However, if your MBP did not come with disks (my new 15-inch for my son has Lion and no disks), then it's impossible to downgrade to SL. There are no published SL disks that include your 2011 hardware, and without those drivers the install will fail when it sees it doesn't support your hardware. If you know someone with a 2011 MBP with SL disks, those will probably work with your MBP.

    That said, there are some VERY complicated workarounds to use the published SL 10.6.3 disks involving getting the SL Kext files from an MBP with SL, but that's not for the faint-of-heart. When many people did this to convert the 2010 Mac Mini Server to SL Client, the installation was able to be forced but things like wi-fi still didn't work properly.
     
  4. mrmister thread starter macrumors regular

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  5. Icy1007 macrumors 6502a

    Icy1007

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    #5
    If you have the discs, it will work. If you don't then you can't do it.

    It's not a matter of "trying to do it"

    If it comes with Lion, just use Lion.
     
  6. AdrianK, Aug 3, 2011
    Last edited: Aug 3, 2011

    AdrianK macrumors 68020

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    #6
    You'll probably need to 'acquire' a 10.6.6 restore disc from a 2011 MBP, because they were shipped with a modified build of 10.6.6 which you won't find on a retail SL disc.

    EDIT: Everything PenguinMac said :p Obviously it will work with restore discs because those discs work on the very same hardware, the OS the MBP comes with is irrelevant (in this case).
     
  7. Icy1007 macrumors 6502a

    Icy1007

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    #7
    My 2011 MBP shipped with 10.6.6
     
  8. AdrianK macrumors 68020

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    Feb 19, 2011
    #8
    Then I'm being a n00b.

    Still, you'll need 2011 MBP restore discs to downgrade to SL.
     
  9. Mac-key macrumors 6502a

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    Alabama
    #9
    ok, so just to be clear... IF I bought a 2011 MBP today, and it shipped with Lion and NO SL install disks, I couldn't use my retail SL disk to clean install the OS???

    What if I just swapped out my HD in my 2009 MBP with SL on it? Or what if I just cloned my old drive to the new one? would this work??
     
  10. kappaknight macrumors 68000

    kappaknight

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  11. mrmister thread starter macrumors regular

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    Dec 19, 2008
    #11
    So I will need to find a SL disc that boots 10.6.6 if I want to try this, it would appear.
     
  12. Gallium Spoon macrumors newbie

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    Jul 28, 2011
    #12
    Why would you want to do that?
     
  13. PenguinMac macrumors member

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    May 21, 2010
    #13
    Not quite. It has to be the 10.6.6 build that shipped with the 2011 MBP's, which is usually later than the vanilla 10.6.6 that upgraders received through Software Update.
     
  14. tekkietekkie macrumors member

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    Aug 26, 2010
    #14
    my guess is wifi problems, I just got a 13.3" 2011 MBP today and since upgrading to LION the wifi is dooooog slow, there are quite a few people complaining about it on apples site

    since I just got it today and have spent most of the time trying to figure out this wifi issue I am tempted to go back to sl on it because it worked perfectly
     
  15. mavonnahme macrumors newbie

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    Aug 3, 2011
    #15
    I just got my 15" MBP a few weeks ago and it came with SL. I upgraded to Lion last week because I was curious to see how it was. After I upgraded I noticed my machine was running hotter, fans louder, battery wasn't as good, etc. etc. Also I wasn't impressed with mission control and launchpad. Needless to say I successfully downgraded to SL using the discs that came with my machine, but I kept getting kernel panics and stuff. I ended up wiping my harddrive and reinstalling SL since I hadn't put too much on my machine yet. So yes it's possible but it might be a little buggy. I'm not a tech pro by any means so maybe I didn't do something properly when I downgraded but who knows. Just back up your stuff before switching OS's and take comfort knowing if everything goes terribly wrong you can do a full wipe and clean install.
     
  16. Nermal Moderator

    Nermal

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    #16
    I'd be interested to hear what happens if you call Apple and ask for disks. After all, the "What's in the box" section of the specs states that software DVDs are included...
     
  17. mrmister thread starter macrumors regular

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    #17
    "Why would you want to do that?"

    I think it is a little sad that on a site like this people would honestly wonder why someone would want to control what software is running on their machine.
     
  18. mrmister thread starter macrumors regular

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    Dec 19, 2008
    #18
    I got ahold of an install disc for a 15" 2011 MBP...if I choose to upgrade, then I should be able to downgrade the 2011 models, unless they make other changes to them.
     
  19. Macsavvytech macrumors 6502a

    Macsavvytech

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    May 25, 2010
    #19
    There are plenty of people who still need to run PowerPC Applications for work. Some product don't have a choice!

     
  20. bigjobby macrumors 65816

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    London, UK
    #20
    You'll have to wipe the disk and do a clean install of SL. Don't think you can 'downgrade' as such.
     
  21. mrmister thread starter macrumors regular

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  22. softasfur macrumors newbie

    softasfur

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    #22
    I just did it. You need to install 2 video kexts from lion to SL. search kexts com
     
  23. snaky69 macrumors 603

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    Mar 14, 2008
    #23
    If you can source the recovery DVD's for an early 2011 MBP, then yes, you can.
     
  24. tweedierhail macrumors newbie

    Joined:
    Aug 9, 2011
    #24
    Its possible

    1. Using disk utility in Lion, you can divide up your current partition in order to dual boot lion and snow leopard.
    2. You can boot from the snow leopard disk and reformat the whole drive to create 1 snow leopard partition by using the disk utility under "utilities"
     
  25. SlyGuyJ macrumors newbie

    Joined:
    Aug 9, 2011
    #25
    If it helps any i just downgraded from Lion using my SL retail OS disks because OS X Lion sucks with wifi connections, i did a clean install via disc boot (power on & hold C) & voila im back on SL.
     

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