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

Hi all,

the following instructions were provided to me by our Apple Enterprise tech, and I've successfully performed these steps on a newly purchased MacBook Pro.

Please note the following - as of 15 Aug 2011:

- this technique will work on new MacBook Pro, Mac Pro or iMac computers UNTIL Apple modifies the hardware in these computers

- this technique will NEVER work on currently shipping MacBook Air or Mac Mini computers

- this configuration of Snow Leopard installed on a computer that shipped with Lion is not supported by Apple Support. It is entirely possible that after a trip for an AppleCare support incident, or the Apple Genius Bar, that the computer will return with Lion installed.

with these caveats, here are the step-by-step instructions:

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HowTo - NetRestore - Install Mac OS X 10.6.8 on new Mac delivered with Mac OS X 10.7.0

note: this only applies to Macbook Pro, Mac Pro, and iMac computers that originally shipped with Mac OS X 10.6.x.

Current Macbook Air and Mac Mini computers cannot be downgraded.

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 (download from Apple Support Downloads page)

- System Image Utility 10.6.8 (download Mac OS X 10.6.8 Update Combo v1.1.dmg from Apple Support Downloads page)

Procedure:

A. Create the NetImage:

1) mount the base source image (Mac OS X 10.6.3.dmg - created from Box Set Installer)

2) launch System Image Utility (from Server Admin Tools)

3) when source (from mounted image) appears in SIU screen, click Custom button

4) drag "Customize Package Selection" from Automator Library window to location

between existing "Define Image Source" and "Create Image"

5) drag "Add Packages and Post-Install Scripts" from Automator Library to location

between "Customize Package Selection" and "Create Image"

6) in the "Customize Package Selection" section:

a) expand the "Mac OS X" triangle

b) select options desired

c) collapse the "Mac OS X" triangle

7) mount the appropriate update image (Mac OS X 10.6.8 v1.1 Combo.dmg)

8) copy the MacOSXUpdCombo10.6.8.pkg package to a new local directory (Desktop/parts/)

9) drag the MacOSXUpdCombo10.6.8.pkg icon from local directory to the

"Add Packages and Post-Install Scripts" section of the SIU window

10) in the "Create Image" section:

a) select the type "NetRestore"

b) set the "Installed Volume:" field to "Macintosh HD" (no quotes, can be any name)

c) select the "Save To:" location

(will be faster to a second local internal disk)

(not faster to another partition on the same disk)

d) set the "Image Name:" field to "Snow Leopard 10.6.8 NetRestore"

e) the fields "Network Disk:", "Description:", and "Image Index:" don't

matter unless one is going to use results on a NetBoot Server

11) click the Run button

12) when the dialogs appear, ignore the text and click OK for proper completion

Dialog text: "Image creation in progress.

Cancel the image creation to proceed"

B. Post-process to create Restore Image:

1) find the directory created in the above process, named as in A.10d above

(Snow Leopard 10.6.8 NetRestore.nbi)

2) in this directory are three files:

- i386

- NBImageInfo.plist

- NetInstall.dmg

3) mount the NetInstall image (double-click the NetInstall.dmg file)

4) navigate into the Contents of the package, to: System/Installation/Packages/

5) copy the System.dmg file out to desktop or other work location

6) rename System.dmg to meaningful name, such as "Snow Leopard 10.6.8 System.dmg"

7) copy this .dmg file to external, bootable, Snow Leopard 10.6.8 system disk (install in /Users/Shared/)

C. Install Snow Leopard 10.6.8 on new MacBook Pro or Mac Pro

via command line:

1) boot MacBook Pro or Mac Pro from external source prepared in B.7

2) open Terminal

3) find the restore target device specification

a) run the command "diskutil list"

b) look for a 650 MB partition, labelled "Recovery HD" (likely disk0s3)

c) the target partition should be immediately prior to the "Recovery HD" partition

d) for a new computer with a 500 GB drive, this partition should be

labelled "Macintosh HD", with a size of 499.2 GB

e) make note of it's Device Identifier, likely disk0s2

4) issue the following asr (Apple Software Restore) command

sudo asr restore --source "/path/to/restore.dmg" --target /dev/disk0s2 --erase

(replace "/path/to/restore.dmg" with the path to the location and name used in step b.7)

5) this process proceeds and completes quickly, about 3-5 minutes. This is due to

the "--erase" parameter; it indicates a block-copy operation

If the process seems slow, likely the "--erase" option was omitted and

the copy is being done as a file-copy operation. Quit (ctl-c) and

examine the command used...

via DiskUtility GUI:

1) boot MacBook Pro or Mac Pro from external source prepared in B.7

2) launch /Applications/Utilities/DiskUtility.app

3) select the computer hard drive (typically "Macintosh HD")

4) click on the "Restore" tab

5) click on the "Image..." button to specify the "Source"

6) navigate to /Users/Shared/ and select the "Snow Leopard 10.6.8 System.dmg" file

7) drag the computer hard drive volume (Macintosh HD) to the "Destination" field

(note: grab the volume, not the disk!!)

8) enable the "Erase destination" checkbox

9) click the "Restore" button

10) in the ensuing "Are you sure?" dialog, click the "Erase" button

11) authenticate with the local admin credentials

Apple Tech recommends leaving the Restore partition alone, and installing in the "Macintosh HD" partition only

commands to know:

- asr

- diskutil (diskutil -list to see partitions)

- hdiutil

Posted on Aug 15, 2011 9:00 AM

Top-ranking reply

zirkenz

Level 1

0 points

Posted on Sep 9, 2011 6:28 PM

okay i got to step:

b7) copy this .dmg file to external, bootable, Snow Leopard 10.6.8 system disk (install in /Users/Shared/).

Don't understand what this means. Right now i copied to my imac desktop and renamed the system.dmg file (from the netinstall mount, system/installation/packages) as you said to Snow Leopard 10.6.8 System.dmg. This file is ow sitting on my imac desktop. What do i do next? I dont understand part b7. Where is the external bootable snow leopard system disk and where is install in /Users/Shared/ ?

by the way the renamed system.dmg file to Snow Leopard 10.6.8 System.dmg is 4.82gb (actually they both are) is this right?

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364 replies

Roy Miller Author

Level 1

32 points

Aug 22, 2011 1:22 PM in response to Karina_T

Karina_T wrote:

Should also add that the dmg I downloaded from apple support - combo updater for 10.6.7 early 2011 MBP

http://support.apple.com/kb/DL1368

doesn't want to run on the new mac either...

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

Karina_T

Level 1

0 points

Aug 23, 2011 2:19 AM in response to Roy Miller

Hi Roy,

Yes, I also kind of worked it out that 10.6.8 would be the only version that would work on my new mac.

I'm back into the Applestore today where they'll look at it but I realise now I'll just have to go with 6.8 and use the new beta for PT9 and thankfully, there's an M-Audio driver for 10.6.8 now for my interface.

Not quite ideal but at least a workable compromise in the meantime.

Thanks for taking an interest in my plight!

Aug 25, 2011 6:21 AM in response to Roy Miller

Roy,

Thanks for the very helpful post. But I do have one question. How do I get the "base source image "Mac OS X 10.6.3.dmg' " from the box set start up disc. When I use disc utility I get a disc image for the whole dic entitled "Mac OS X Install DVD.dmg" This was created using the Snow leopard 10.6.3 box set installer. Is this the correct image?

Thanks,

Mark

Roy Miller Author

Level 1

32 points

Aug 25, 2011 7:50 AM in response to jsd2

jsd2 wrote:

Roy Miller wrote:

I would recommend the following path:

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

A G4 (ppc) can't run Snow Leopard.

duh! of course! yet another brain-glitch 😉

Aug 25, 2011 11:27 PM in response to Roy Miller

I am sorry if this seems tangent to your post topic, but can/will your method work with dual booting Lion/SL ? There are a number of 3rd party educational programs that will eventually catch up to Lion but currently do not support it (Smartboard, EBeam, LotusNotes7). If one was looking for a short term (1 year or so) fix and Hd space was not a huge concern other than program files (not movies or anything like that) Would the methodology be the same except with partitions like most dual boot descriptions? (Is there some conflict with the lion restore partition in conjunction with A SL partiton?).

There is a chance that I will have to do this with 9 MBPs that arrived 7/2011 and your image process looks as though it would mean imaging 10.6.8 once and then mounting it in 9 MBPs... I hope I have that right. Does it matter if the computer running 10.6.8 is a desktop when you want to load these onto a MBP? I assume from your post ...no.. but I didn't see anything explicitly saying so and I am somewhat paranoid about my own ignorance.

Thank you for listening and your original post

Will

Roy Miller Author

Level 1

32 points

Aug 26, 2011 11:05 AM in response to Princess Productions

Princess Productions wrote:

I messaged earlier that I couldn't make it work - but I did. I had only updated to 10.6.7 but what I needed was 10.6.8 - I set the new mac up as a target drive and installed SL on a parition. I then ran the 10.6.8 combo update. Thanks for letting me know that I needed 10.6.8!! 🙂

Yes, the new 2011 MBP was not in production when 10.6.7 was compiled - therefore the MBP must have OS version 10.6.8 or later!

glad it worked for you! 😎

Aug 29, 2011 7:47 PM in response to Roy Miller

@Roy, FANTASTIC! I was afraid I would not be able to get this running on a non-Apple SSD in my new MBP but lo' your posted method worked a treat. I am thrilled. Thank you so much for your thoroughness! YES!

Roy Miller Author

Level 1

32 points

Aug 30, 2011 7:17 AM in response to dominic01

Hey Dominic,

glad it worked!

I ended up getting a little lost at part C and resolved the situation by putting the new mac in target mode and running the install from my old mac. I guess this process would probably negate the need fro an external drive??

such things as these are always a bit of an adventure. There are several ways to use a variety of disks, thumb drives, or other computers to complete the 'retrograde'. I didn't want to confuse the procedure any more than it may already be by offering a bunch of options - tried to keep it linear and understandable.... 😉

"understandable" - that's a bit of a laugh! However, I suppose the procedure is more understandable once someone has gone through the steps once (or more!?)

you are welcome.

Sep 1, 2011 10:35 AM in response to Wanky

Hey Guys,

My iMac came with Lion. My music software Logic 8 is no longer compatible, and I don't wanna blow $400 on Logic 9 if I don't have to.

Is it possible for me to partition my drive such that I can keep lion but install snow leopard on a smaller partitioned disk?

Wanky said "I can now dual boot Snow Leopard and Lion on my new MacBook Pro which came with Lion." How did he do this?

I am pretty inexperienced with all this, so if I'm asking stupid questions, forgive my ignorance. 😉

Sep 1, 2011 3:34 PM in response to Roy Miller

bad news. I "opened System Preferences and selected the "Startup Disk" preference pane. in there, selected my Snow Leopard disk, and clicked the "Restart..." button." And now every time i reboot it can't get past the apple, and this grey screen with a bunch of random text goes over it and it tells me "Restart Your Computer."

AHH?

I can't eject the disk, and I can't do anything.

Help?

Thanks.

zirkenz

Level 1

0 points

Sep 1, 2011 9:11 PM in response to zirkenz

i figured out the time machine thing. The partition thing all i have discovered so far is that i have to repartition as one drive and then reinstall or stay that way. If anyone knows an easier way pls let me know. As for the speed thing still the same no solution. (should not be happening) By the way someone figured out how to install SL on the new mac mini 2011. The thread is in this forum. Can you guys who downgraded from a preinstalled lion do a geekbench using the free 32 bit version and then compare your results with scores on the net or even on geekbench site. I'm curious to see if this issue is universal.

Sep 2, 2011 12:00 AM in response to Roy Miller

Roy,

Succeeded in dual booting MBP this afternoon after trying (just to leave no stone uncovered for my boss) the conventional methods that wold. work for a MBP circa 2009. or so. Then had to find a machine to run 10.6.8 on to do part A. Then needed a machine to do part A on that had more than 10 GB of available space to create the files (a mistake on my part partitioning a computer to run 10.6.8). Then. I did it at home on my Imac and brought the dmg to work. Part C was surprisingly fast, and part A was long as you had warned. So thank you. One down, eight more to go. For others reading these threads I used target mode on the MBP after I looked up what it was and purchased the appropriate 800 to 400 FW adapter. Very simple with the instructions (so thank you to the poster of that tidbit, it helped too).

My only last question is one about the licensing. 9 MBPs, 2 SL family packs. Can I just clone the one created image 9 times or will I have to clone 5 from one family DVD and then 4 from another? I am assuming that I am not doing step A 9 times because life cannot be that cruel. And tech is supposed to improve our lives right? .... right?....

Again Roy, and those that have contributed to this thread, many thanks.

William

Roy Miller Author

Level 1

32 points

Sep 2, 2011 9:56 AM in response to zirkenz

Hi Zirkenz,

for a) simplest way I know is to clone your installed system to an external disk, using SuperDuper or CarbonCopyCloner, for example. Then, boot from the clone, repartition the iMac hard drive, and restore the system by cloning back from your external clone. Beware, this method will, and should, completely erase your external disk prior to creating a clone.

for b) I suspect your benchmark problems stem from installing Snow Leopard 10.6.3 on the iMac. This version of hardware is not supported by the drivers embedded in v10.6.3. Even though you upgraded to 10.6.8 eventually, it may be that drivers were not properly updated for some of the iMac hardware components. Of course, I'm just huffing and puffing, because I've never had nor worked with the Apple iMac model. I've personally interacted with almost every Mac Mini, MacBook Pro, MacBook Air, Mac Pro model, so for these I can speak/write more from personal experience. We could also discuss most PPC models back to the Mac II, but that is not the topic here.

for c) it depends. If you are using Time Machine to backup to a "local disk", Time Machine should just create a hierarchy of folders and files. If you are backing up to a non-local disk, such as a server volume, or probably a Time Capsule (again, no personal experience with this device), Time Machine wraps this folder hierarchy in a "package" wrapper, that appears to be a single file. I've been told this is a "sparse bundle" and one can get to the enclosed files from Finder by a method. I can't remember if it is double-click to mount, or right-click to examine package contents.

cheers!

Roy Miller Author

Level 1

32 points

Sep 2, 2011 10:03 AM in response to williamfromkailua

Hi William,

yup, Tech Harmony has got it right AFAIK. Glad to have you on the thread, Tech!

you may legally install as many instances of the OS as you purchased licenses for. They may be installed from any of the media you have supported by those licenses. You get to be one of the "lucky" ones here, in that you need only do the slow hard part of the procedure once (Parts A & B) and can then perform the much quicker install (Part C) as the repetative portion of your tasks!

good luck with your installs!

Roy Miller Author

Level 1

32 points

Sep 2, 2011 10:09 AM in response to zirkenz

Hii Zirkenz,

By the way someone figured out how to install SL on the new mac mini 2011. The thread is in this forum.

I looked at some of that long thread as well. Many seem to report slow and/or problematic operation of the retrograded Mac Minis. Again, my suspicion is that these problems are likely mainly due to new hardware for which no correct drivers exist in any version of Snow Leopard.

Install Snow Leopard on a new Mac Mini - can it be done? Sure, probably.

Would you do this, and give the result to your boss? I wouldn't.

Can you guys who downgraded from a preinstalled lion do a geekbench using the free 32 bit version and then compare your results with scores on the net or even on geekbench site. I'm curious to see if this issue is universal.

I've never used geekbench, however I'd question results from a 32-bit test on what now are pretty completely 64-bit machines and systems. Maybe it doesn't matter.....

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