HowTo revert new MacBook Pro, Mac Pro or iMac to Snow Leopard

Hi Shezan,

I highly recommend that you carefully read all the posts here.

If i have the mac box set with 10.6.3 can i erase the HD and install SL that way?

the answer to this is in my post immediately preceeding yours....

the new Macs only run under OS X 10.6.8, 10.7.0, or 10.7.1......

based on the description of your situation, which for some reason is not displayed in this thread, but was on the email I received from your post,

Shezan Hirani wrote:

I'm kinda in a bind, i bought a mid 2011 imac from a 3rd party reseller who insisted the sytem had SL prior to purchase but when it arrived it has lion. My old imac is a g4 20" with tiger and i just found out that i cant migrate my emails to lion. I can from SL. So going back to SL is critical for me. Before SL came out an Apple genius said if i bought the mac box set i could revert any future system, Lion for sure, so i bought a family pack thinking i'd wait for the new systems and then downgrade those and then after lion i was told that was not possible. If i had know i would have ordered my imac before hand.

I would recommend the following path:

- upgrade your G4 iMac to Snow Leopard 10.6.3, using the box set

- this should then upgrade your Mail database to an appropriate level for migrating to Lion

- remain on Lion with your new iMac, and migrate your account(s) from the old iMac using the migration assistant

if you really feel that you need to "downgrade" the new iMac to Snow Leopard 10.6.8 (the only Snow Leopard option), please make sure that you have the necessary resources, as described in earlier posts. To do this, you will need to have access to a computer running Snow Leopard 10.6.8, so you may have to upgrade your G4 iMac in any case.

here are the resources necessary (from my initial post, with the SIU reference corrected):

Required resources:

- another computer, running Mac OS X 10.6.8

- spare external disk

- Snow Leopard installation disc

(Mac OS X 10.6.0 or 10.6.3 Box Set)

- Snow Leopard 10.6.8 Combo image file

(Mac OS X 10.6.8 Update Combo v1.1)

(download from Apple Support Downloads page)

- System Image Utility 10.6.8

(Server Admin Tools 10.6.8)

(download from Apple Support Downloads page)

if you do proceed, please print out the initial post, and read and follow the directions carefully.

Good luck!! 😀

Callofdude - you can follow the instructions for creating 2 partitions on the disk containing your "Macintosh HD" volume, however, then you are still going to have to go through the process, performing all parts A, B, and C, to create a version of Mac OS X 10.6.8 that will boot your new iMac. Then, instead of erasing the whole disk and installing the system, in Part C, Step 3, under the Diskutility GUI method, you should select the new empty partition you created following Nanotechie's instruction.

Prior to doing any of this, you should convince yourself that whatever Snow Leopard disk you have does not successfully boot your iMac. A variety of methods to test this are:

insert you Snow Leopard system installer disk, and do one of the following:

- reboot, and hold down the C key (should then reboot from the optical drive)

- reboot, and hold down the option key. after a while, you should see the bootable disk. If your Snow Leopard install disk appears, after the cursor has turned back into an arrow, click on the Snow Leopard disk, and click the right arrow to continue

- instead of rebooting, after you insert the disk, open System Preferences and select the "Startup Disk" preference pane. in there, select your Snow Leopard disk, and click the "Restart..." button

to really see what is going on with the boot process, and especially to see where/why a boot is hanging, before restarting, open a Terminal window and enter the command:

sudo nvram boot-args="-v"

you'll have to enter your (administrative) password, due to the sudo command. This should be you regular password, if you regular account is the administrative account on the computer.

this will turn on verbose boot and shutdown, and instead of a bland window with a circle of sticks rotating while the computer boots, you'll actually get to see what is being loaded as the system boots up.

to undo this setting, enter the command:

sudo nvram boot-args=""

cheers!

Hey Josh,

my understanding is that currently selling Mac Mini and MacBook Air models now contain hardware for which drivers were never incorporated in any version of Snow Leopard. Therefore, no version of Snow Leopard can fully run these computers, or ever will.

with that statement, it probably depends upon just which hardware was upgraded. For example if is just the wireless network system components that were upgraded, and you don't use wireless, then perhaps a current Mini would run under Snow Leopard, if you could find a way to install it.

Do you know if the applecare warranty is Void, or if there is just no suport when installing SL on a Lion iMac?

I was told that this is "not a supported configuration for these currently shipping Macs" (MBP, MP, iMac). I was told that this would not void my warranty or AppleCare, however if I took one of these in to Apple for service, it could end up being returned with Lion installed, instead of the Snow Leopard system I've installed.

This info was from an Enterprise Apple Technician, who supports our enterprise deployment.

For me, I always clone the hard drive prior to turning a computer in for service. Usually I make two clones, to keep the gremlins at bay! 😉 Therefore, if it came back from service with Lion installed, I'd just revert from my clone....

Have you done any geekbench scores to know if permance has been affected at all? I know with the minis being reverted via target disk mode, that they are suffering some significant performace issues. Likely as disucssed related to Lion hardware not being able to access drivers from SL install.

I haven't. To be clear - I've perfomed this procedure on a MacBook Pro 15", that has since gone to one of my users. I also have a Mac Mini, that I bought specifically to run under Lion, and explore that system. Although I've gone through some hoops to reformat the disk and re-install Lion on the Mini, I've not even tried to retrograde the system to Snow Leopard.

I suspect it is as you say, that the performance issues are due to Snow Leopard not having the correct drivers integrated in the system for the current hardware configuration.

glad this thread has helped at least some folks. It likely won't be too long before new hardware has found its way into MacBook Pro, Mac Pro, and iMac models, and then we'll really have problems retrograding systems.....

cheers!

so, it sounds like you have a Mac Pro already running Snow Leopard. This is good news, as this is a good fast system on which to perform the long Part A of the process.

...install snow leopard from there with brand new snow leopard install disks. Shouldn't this work as a work around for Mac Pro users?

It is highly likely that you don't have a system install disk that can install a "proper" system on a 2-day old Mac Pro. If you do have an installer that will boot the new Mac Pros, then you probably should use that.

I suggest that you make sure your Snow Leopard system is up to 10.6.8, then download and install the Server Admin Tools 10.6.8 on it. Follow the steps in Part A, let it simmer for a couple hours, and you'll be able to extract a system image file in Part B that you can use for each of your 2 new Mac Pros. Please note - this is not an installer! This is an image of a system that will replace the contents of your second internal hard drive on the 2 new Macs, using the methods in Part C.

hope this helps...

I bought a family pack snow leopard disc brand new from a certified mac seller today. not an actual mac store. I called a mac store and know they have pulled all the discs from their retail stores. should these discs work for me?

no.

The only version of Snow Leopard that will run 2-day old Mac Pros is version 10.6.8. No such retail discs were ever distributed by Apple.

The family pack likely has either Snow Leopard version 10.6.0 or 10.6.3. These are the only retail versions of Snow Leopard that I'm aware Apple has released. Since these versions of the OS software won't properly run the 2-day old Mac Pros, due to changes in hardware, such as video cards, processors, etc., you need to somehow get Snow Leopard 10.6.8 onto your new Mac Pro boot disks.

Therefore this procedure.

As I've counseled others, the procedure seems complicated and is hard to envision, until you've actually gone through it (once or twice). I recommend you try to get through Part A, taking some of it on faith, and recognizing that the initial post gives the wrong name of the source file for the package contiaining the System Image Utility. It should say "Server Admin Tools 10.6.8.dmg".

give it a shot...

Glad it worked for you Blair!

Is there any way to use this process or another to create a bootable DVD or mount that I can boot from, partition and install 10.6.8? When I used your process I was able to install Snow Leopard but I couldn't partition the internal drive. I want to be able to create two partitions, one for Snow Leopard and one I can Boot Camp Windows on.

I would say that in Part C, when the new MBP is booted in target mode, and Disk Utility is being run on the "other" Mac, you could easily then partition the hard drive of the new MBP in whatever fashion you like, as long as you leave enough space on the "Mac" partition to hold the system and desired files, etc.

so, after step C.3, and before step C.4, go to the "Partition" tab in Disk Utility, select the new MBP hard drive, change the pull-down menu from "Current" to "2 Partitions". Adjust the size as needed. Select one partition that you will use as the "Restore" target, click the "Options" button. Select the "GUID Partion Map" option. For the Boot Camp partition, I believe you will want the "Master Boot Record" option. Once these are set, and the partition sizes selected, Apply the settings.

When done, continue with step C.5, selecting the partition you've designed for Mac OS X as the target destinaton. This should all proceed quickly.

If you've saved the "restore" source file created from Parts A & B, you don't need to do that all again, just the Part C, modified as described.

In regards to a bootable DVD, etc., this procedure does not produce an "installer". However, after completing the install of the system, you could use SuperDuper or Carbon Copy Cloner to clone the freshly installed system to another disk, such as an external Firewire disk. As I' ve learned through discussions of this procedure, that disk will boot any Mac capable of booting from Snow Leopard 10.6.8.

You might be able to burn this to a DVD, double layer I suspect, using Toast or some such. Probably have to do so on the "other" Mac, while the new MBP is booted in Target Disk mode.

cheers!

Hi JimTet,

Tech Harmony provided an answer for you:

@jimtet, Doesn't sound like the Apple Techs you reached were able to run through "The Procedure".... it does work for iMac folks but the verdict for iMac'cers is that you'll get more performance if you request and utilize the factory install discs from Apple. If you call Apple back, they should send you the discs for 0-15$, depending on who you get. These special factory install discs for your iMac are probably all-white and have a version of 10.6.6 or 10.6.7 that was especially made for your iMac.... then you will be able to update from there as you please.

This suggested method would likely be the easiest method to install Snow Leopard on a new iMac. The key to whether installing Snow Leopard on a computer released with Lion installed is the degree to which hardware changes have made in the Lion-release iMac, or if the hardware is the same that was released with Snow Leopard.

A couple of thoughts have occured to me, regarding your situation. First, the disclaimer: I've never worked with an iMac, so have no first-hand experience with them. My recent Mac exposure has been limited ( 😉 ) to: Mac Pro, MacBook Pro, MacBook Air, MacBook, Mac Mini, and Xserve.

anyway, that aside, I have two suggestions:

- try connecting your two iMacs via firewire, and booting the new one from the 2006 iMac with Snow Leopard installed. I've never tried exactly this myself, so there may be some reason why it wouldn't work.

This process would be:

1) power up the new 2011 iMac

2) with the old 2006 iMac off, connect a firewire cable between the two iMacs

3) power on the old 2006 iMac, holding down the "t" key

4) when the firewire icon starts gliding across the old 2006 iMac screen, release the "t" key

5) when the old 2006 iMac disk appears on the desktop or mounted Volumes area of a Finder window on the new 2011 iMac, open System Preferences.

6) in the "Startup Disk" System Preference Pane, select the old 2006 iMac disk to boot from

7) enter passwords in the ensuing dialogs if necessary, and click the restart button when offered

if the system boots, and runs, and your apps function, you will know that the new 2011 iMac runs fine from Snow Leopard. You can use Carbon Copy Cloner or SuperDuper! to clone the old 2006 iMac system to a clean external disk, and use that disk to boot and run your new 2011 iMac.

Note: to make the Target-mode boot process above easier, it might be worth renaming your disk on the old 2006 iMac to something unique, if not already done. It can be hard to figure out which "Macintosh HD" volume is which, when there are more than one!

The other idea is to run "The Procedure", with an install target (Part C) of an empty external disk. Once completed, this could be used to boot your new 2011 iMac in Snow Leopard, while maintaining the Lion installation on the new 2011 iMac internal disk.

so, options abound - unfortunately there is no remedy that is not a bit of an adventure. Only you can decide whether it is a worthwhile endeavor for you to attempt to revert a Lion computer to Snow Leopard.

cheers!

@rsx-s - the bottom line of whether you can boot a current Mac from a Snow Leopard disk and have full support of all the hardware in the new Mac depends upon whether new hardware components have been integrated into the current version of the Mac in question since Lion was released.

If no hardware changes were made, then the current Mac can run under at least Mac OS X 10.6.8, and perhaps slightly older versions, if the hardware configuration ever shipped with the earlier version of the OS.

Once hardware changes have been integrated into the computer, the older systems won't support that new hardware - the drivers were never compiled into the older OSes, because of course, such a configuration didn't exist when the older version of the system was compiled!

One thing is for sure - none of the "retail" versions of Snow Leopard (v10.6.0 & v10.6.3) will boot any of the currently offered hardware. Therefore "The Procedure" and its derivatives and alternate methods, as discussed in this thread.

It makes no difference whether the Snow Leopard OS is installed on the internal hard drive, a partition on the internal hard drive, or an external hard drive.

Regardless of any of our (the Users) desires, we will all eventually be running Lion or a later OS version on our newly purchased Macs, or have switched to non-Mac alternatives.

One of the easiest methods I've heard of, included in this discussion thread, is to call Apple Care and ask for a grey boot disk for the MacBook Pro as it was delivered immediately prior to the release of Lion. This is likely Snow Leopard version 10.6.6 or 10.6.7. It may cost $15-$20 to get - but if it will boot your new MBP, then you can install from that and upgrade to SL 10.6.8 via Software Update.

cheers!