Downgrading mid 2011 imac from 10.13 to 10.6

Discussion in 'iMac' started by C. Alan, Oct 22, 2018.

  1. C. Alan macrumors 6502

    Jan 23, 2009
    Ok, I have a bit of a challenge here....

    My 80 year old dad is used to using 10.6 (snow leopard), and does not want to upgrade. Recently his 2006 Imac died, so I purchased for him the last Imac that natively runs Snow Leopard (a mid 2011 Imac).

    Now the problem... It came with High Sierra installed on it. I have a retail copy of 10.6, but the computer won't boot that. So I am going to contact apple tomorrow and order a copy of the original recovery DVD for the machine.

    In the course of doing my research on this, I found out that several EFI upgrades have been pushed since 10.6, and I am wondering if they will prevent me from installing from the recover DVD. Does anyone have any experience trying to do this?
  2. snow755 macrumors 65816


    Sep 12, 2012

    i dont think you be able too run 10.6 on a 2011 Imac could be wrong
  3. robbier macrumors member

    Apr 27, 2008
    The firmware upgrade won't affect booting and installing 10.6, but you will have to get your hands on the original restore discs for that originally came with 10.6.6 so any retail snow leopard disc will not boot. Apple may be able to sell you the original restore discs with 10.6.6 - it is worth asking.
  4. AnonMac50 macrumors 65816

    Mar 24, 2010
    If you can run it in target disc mode from another Snow Leopard supported Mac, you can install Snow Leopard, then upgrade to 10.6.8, it would work.
  5. C. Alan thread starter macrumors 6502

    Jan 23, 2009
    Interesting.... My Dads old mac wills still boot and run (its fans are failing very loudly). It is a 2006 running 10.6.8. I will have to look into this.
  6. mikehalloran macrumors 65816

    Oct 14, 2018
    The Sillie Con Valley
    The restore disk for a 2011 iMac is 10.6.3.

    A 10.6.0 retail disk will not boot a 2011. Been there, tried that.

    If Apple can't send you the correct Restore DVD for any reason, I should still have mine somewhere. Dropbox is good for sharing disk images.
  7. Fishrrman, Oct 23, 2018
    Last edited: Oct 23, 2018

    Fishrrman macrumors P6


    Feb 20, 2009
    I checked, and it shows that at least some 2011 iMacs could run 10.6.6.

    The retail copies of "Snow Leopard" (that came on a DVD) -I think- were 10.6.3.
    What this means is that the version of 10.6 on the DVD is "too early" to boot the iMac you have.

    I'm going to -guess- that what you need to do is download an "upgraded copy" of Snow Leopard (and what follows is important) from a source other than Apple. Yes, this means "unauthorized". But I don't think there's any other way to do it.

    Hmmmm.... check Mike Halloran's reply to you above.
    He might be able to help.
  8. AmazingRobie macrumors 6502


    Jun 10, 2009
    Target disk mode:

    Use FireWire cable to connect computers. Easiest way. Then once installed, make a clone image with Carbon Copy Cloner free version and tuck it away somewhere.

    I purchased the twenty dollar SL restore disc from Apple for our mid-2011 iMac and it never got used but once.

    10.6.8 is rock solid and fast, but turn the brightness down to about halfway on the display if you can (80 year old eyes probably might have an issue) and install something to monitor your internal temps like macs fan control. Make sure it doesn't get too hot because it will cause the GPU to burn itself out early if you don't keep your eye onit.
  9. mikehalloran macrumors 65816

    Oct 14, 2018
    The Sillie Con Valley
    Mine is the iMac Restore Disk. Apple sent me free but I was still under AppleCare. It might actually be 10.6.6 but I'm remembering 10.6.3. Anyway, pretty sure I still have it. I had to use it on my wife's 2011 once. Do call them—you never know.

    I still have the retail Snow Leopard disk—you had to buy those. It would boot my 2010 but not her 2011.

    The firmware updates that High Sierra runs do not keep your machine from running older OS. My 2010 is on High Sierra but I have test drives running Lion and El Cap and they boot it just fine over USB 2.
  10. FlorisVN macrumors 6502


    Nov 8, 2013
    as far as I know, you can use MacOS 10.6.7 install dvd.
    since 10.6.7 there is sandy bridge support for Snow Leopard.

    I think the original dvd's that came with the iMac, contain 10.6.7 Snow Leopard built.

    However, easiest way is put iMac 2011 in target disk mode, and clone a 10.6.8 snow leopard install to it.
    Then It should boot fine...
  11. StellarVixen macrumors 68000


    Mar 1, 2018
    Really? When OP said:

    It's not that hard, you just have to read people's posts it a little bit more carefully...
  12. EugW macrumors 603


    Jun 18, 2017
    I know this is not on topic, but...

    10.6 is not recommended, even for your 80 year-old dad. Current browsers are not supported, which means some websites will simply not work properly, and sometimes not at all.

    If he surfs the internet on it, he really should consider using a more modern version of the OS. It doesn't have to be High Sierra, but Snow Leopard is a big problem.
  13. C. Alan thread starter macrumors 6502

    Jan 23, 2009
    He is not surfing on this computer.. It has more to do with being able to run old financial software he has been using for years that is now outdated.
    --- Post Merged, Oct 23, 2018 ---
    Well apple support did not come through for me... Their advise was to take it back to the apple store to have it restored. I'd rather not make that three hour journey. If you would be so kind as to drop box it, it would be appreciated.
  14. FlorisVN macrumors 6502


    Nov 8, 2013
    If needed, I can share my 10.6.7 snow leopard iso.

    Just let me know...
  15. Fishrrman macrumors P6


    Feb 20, 2009

    There are various ways to get a copy of Snow Leopard that will run on your dad's Mac.

    These ARE NOT "Apple Authorized" ways, but they exist nonetheless.

    I suggest you learn about them, because I don't believe an "official upgrade path" that will work for you still exists via Apple.
  16. Mr_Brightside_@ macrumors 68030


    Sep 23, 2005
  17. rpmurray, Oct 24, 2018
    Last edited: Oct 24, 2018

    rpmurray macrumors regular

    Feb 21, 2017
    Back End of Beyond
    eBay usually has a few people selling the 10.6.x install discs for iMacs. Just make sure you're getting the right one. According to that would be 10.6.6 or above.

    This seller has them on eBay right now for $10 and free shipping. I've purchased these same discs for a couple of 2011 27" 3.4GHz iMacs that I was able to pick up for cheap recently.
  18. padams35 macrumors regular

    Nov 10, 2016
    Usually macs are limited to no older than the OS that shipped on the particular machine, and while the oldest 2011s shipped with Snow Leopard my mid-2011 (purchased 2012) came with Lion (and had the firmware update for internet recovery instead of DVDs).
  19. RemarkabLee macrumors 6502a

    Nov 14, 2007

    Hi Mr Alan.

    I have the same Mid 2011 iMac. I wouldn't recommend downgrading. I recommend keeping High Sierra as your main system OS (latest supported macOS for this iMac) since it will be maintained by Apple and offer the best security for as long as possible as another poster alluded to. For incompatible legacy software and hardware, I recommend these 2 options:

    1. Install a virtual Mac using VMWare Fusion (pay ware) or VirtualBox (free), to run OS X Lion on top of your High Sierra host OS. With VMWare Fusion it gives you the option to perform an Internet Recovery installation similar to option 2 below (not sure if VirtualBox has this option, but you can install via CD or disk image certainly). You can then use this virtual Mac purely for the accounting software and other legacy software and hardware (I use this method for my old scanner). You'll need enough RAM and hard disk space to run this though, probably 8Gb memory and 50Gb hard disk space. You can start and stop the virtual machine as needed.

    2. Perform a full backup using TimeMachine (just in case!). Create a new partition using Disk Utility, say about 100Gb. Give it a name such as "Accounting". Now reboot the Mac and when you hear the chime, hold down Shift-Option-⌘-R. If prompted, connect to your Wi-Fi base station. Now Internet Recovery should download and run based on "...the macOS that came with your Mac, or the closest version still available.". Last time I did this recently, this was in fact Lion for my 2011 iMac. Select the "Accounting" disk partition as the target disk. After installation, you'll have an isolated version of OS X that will run natively for older software.

    I'd recommend option 1 over option 2 as it'll integrate better with the host OS.
  20. mikehalloran macrumors 65816

    Oct 14, 2018
    The Sillie Con Valley
    Send me a message and I'll reply with my email address. You'll need to share a Dropbox folder with me and I'll upload the disk image. You'll need to burn that image to a DVD and then it should work. If you don't have a Dropbox account, let me know that, too.
  21. AnonMac50 macrumors 65816

    Mar 24, 2010
    I just remembered something. The 2011 iMacs and MacBook Pros had a special copy of the FaceTime app that was not available normally. You can only get it with the restore discs (or by copying it off of a Mac that has it).
  22. C. Alan thread starter macrumors 6502

    Jan 23, 2009
    So I got it to downgrade.
    I used an original recover DVD provided by Mike. However, The disk utility was not up to the task of dealing with the combination of the High Sierra partition, and the recovery partition. I had to make a Gpart CD, us it to eliminate the recovery partition, and decrease the size of the High Sierra partition. I was then able to install Snow Leopard from off the recovery Dvd. Once that was up and running, I restored all of my Dads old settings from off his time machine backup, and now everything works as it should.
  23. mikehalloran macrumors 65816

    Oct 14, 2018
    The Sillie Con Valley
    I was glad to find it. My office is in the process of being remodeled but it finally turned up.

    Alan, I sent an .iso and a .dmg. Which did you use?

    I could not get Disk Utility in High Sierra to create a .cdr — it created the .dmg instead.

    I used Toast to create a .toast file. Changing the suffix to .iso is all one needs to do afterwards.
  24. wicknix macrumors 6502


    Jun 4, 2017
    Wisconsin, USA

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