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

the system.dmg which i renamed is only 4.82gb, the 10.6.3 image is 10.42 gb in system image utility and 6.1-6.6 as a .dmg file and the combo update is 1.09 gb. How does a 4.82gb file contain everything? Is this the right size?

okay, I copied all the files to my imac clone Then i did this:

1) boot imac from my clone

2) launch /Applications/Utilities/DiskUtility.app

2b) reparitioned the imac HD into one drive called Macintosh HD

3) selected "Macintosh HD"

4) clicked on the "Restore" tab

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

6) select the "Snow Leopard 10.6.8 System.dmg" file from my imac clone's desktop

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

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

After it was done i went into System Preferences, Startup disk and was presented with 3 options:

1. Mac Os X, 10.6.8 on CCC (my imac clone)

2. Mac OS X, 10.6.3 on Macintosh HD (my now 1 partition imac HD)

3. Network Startup

I selected #2 from the startup discs option which was labeled as Mac OS X, 10.6.3 on Macintosh HD and restarted. I got a gray screen with an apple logo and the computer started to beep at me very loudly and did exactly the same as if i tried to launch from the mac box set retail disc. So where did i go wrong or has apple locked down the firmware to prevent this from working? So all i can think of is that my system.dmg i created did not include 10.6.8.

Okay so i rebooted using imac clone, and ran the combo updater and selected the Macintsh HD as the destination i.e the imac HD. It installed and it rebooted the imac and i went through all the set up. Ran geekbench and i get the same score as before. So something apparently has gone wrong or this system is locked in some way. This is acting exactly the same way as what i had before.

I'm sure i did part A right, pretty sure about part B did not use cmmand line but went straight to gui and did part c. Somewhere the combo updater did not integrate inot the 10.6.3 creating a 10.6.8 restore image. is yur system. dmg file 4.82 gb?

What would happen if used the Netinstall.dmg (from folder Snow Leopard 10.6.8 NetRestore.nbi folder) to restore? It is 6.5 GB.

🙂 hi thanks for the information i will give it a try, sounds like the best of both worlds,

thanks.

@zirkenz and @Photonomadic

@zirkenz, Almost perfect! You missed the part (A5-A9 of Roy's) where 10.6.8 gets integrated into the original package creation. I remember you asked about which 10.6.8 combo updater to download while you were making the master System.dmg (please see my instructions to you around page #4 where I point out you want version 1.1 and give you a direct link to the file) It occurred to me that if you were asking, then you might have failed to include 10.6.8 in your original process. I didn't want to confuse things by bringing it up but that sounds like what happened. No worries.

The purpose of this process it to create a full virgin 10.6.8 master ... so the idea is to integrate all packages during System.dmg creation (in this case just 10.6.8 for us but other people in this thread were including all kinds of things... keep it simple this round).

But you did a great job and you got the process down almost perfect. Start over (yay) but don't use your old files (trash 'em) because they are only 10.6.3 and there's no sense using compromised files to complicate matters.

[my final System.dmg file size won't help you because it reads even smaller: 4.48GB! But I'm reading the size on a 10.5.8 machine and Apple changed how file sizes are calculated/displayed after 10.5.8 ... your size will definitely be different from mine... but yeah, in the 4.xGB is expected!]

@Photonomadic Apple hasn't updated the Mac Pro for 410 days according to MacRumors' buyers' guide... aside from shipping them with Lion. You should be able to know immediately if you can even boot from the Snow Leopard retail discs you purchased... you can boot the discs without installing. If the Snow Leo retail discs boot in your Mac Pro, they should install fine too.

I've heard speculation in other forums that Apple may tweak firmwares in the machines to keep them from installing older OSes but I personally don't believe that is generally the way Apple locks things down.... and I really don't think they would do that to the Mac Pro line. But you can find this out in 5 minutes by trying to boot from the Snow Leo discs you have.

For the Mac Pros, there is no updated graphics card or processor and you should be good to install Snow Leo normally, to any internal or external drive connected to your Mac Pros. Again, you will find out immediately if you can boot the install discs. If you can't boot the install disc, you should do Roy's method if you really need Snow Leo (or one of the target disc methods people have used).... don't try to understand the whole thing... you can try to use my instructions to @zirkenz around page 4 to supplement confusion 😉 But the Mac Pro line is different from what's going on with these other machines and have been able to boot old versions of Snow Leo for a long long while.... Let us know!

Thanks for the reply @tech harmony,

I have tried to run the software by restarting my mac pro and holding alt to access the boot up drives. The SL retail disc appears but after I click on it the disc never launches. You can hear the disc spinning in the tower but the computer never gets passed the grey apple logo screen. I've waited up to 25minutes and it doesn't go anywhere. I've read about the target disk mode by using another computer and I think that process sounds a little less convoluted. I'm going back into the certified mac retailer today and seeing what they suggest would be the best method to go about this.

I also can't believe that apple would limit people on their highest end machine from the ability to move back and forth between OS's. Especially when Lion is still causing so many problems on the music and video front and thats what most people use these machines for! It shall be an interesting day cause I've got to get this figured out or we will be going with a much more expensive route for our livestreaming gig. I'll keep everyone updated here if anything comes up. Thanks!

Wow... I installed Snow Leo on a client's "new" Mac Pro not 5 months ago. Hmmmm... looking at their machine remotely they have an ATI Radeon HD 5870 .... hmmm looking at the Apple Store this card is the 200$ option and the base card is an ATI Radeon 5770.

Classic.

Well, after you hit option/alt to select DVD boot -- and right after you click on the 10.6.x disc icon -- you could try holding SHIFT to see if you can boot the installer disc into Safe Mode. It's a long shot but it would disable all but the most basic drivers from loading. You hold SHIFT for less than a minute, just before and during the Apple logo.

I don't remember what version you said your retail discs are or if they even indicate....

Good luck today!

@tech harmony,

These machines are only 5 days old and came with Lion already installed. A mac pro from 5 months ago should not have a problem loading snow leopard.

Just went to the certified mac reseller that we bought the towers from and he said that the apple store is offering this service to people with new mac pro's or other models. The reason why the boot up disks wont start is because they are not 10.6.8 which is the ONLY version of snow leopard that will load on these machines. The disks are probably something like 10.6.3 according to the guy at the store. Which makes sense because when i click get more info on the discs in finder they were created more than a year ago, before the final version of Snow leopard.

They'll probably end up doing this same process that roy has so cleverly figured out but I'm just going to let a pro do it and if something messes up it wont be on my head 😉. guy at the store made it sound like the apple store is prepared to do this for people no problem. Im just getting excited for the kind of looks i get when I walk up the genius store with TWO mac towers. This should be fun....

Thanks guys and have a good weekend! Will keep you posted.

Well, they haven't done anything to the Mac Pros in the past 5 months (let alone past year) ... They don't have Sandybridge processors which is the whole point and promise of 10.6.8, far as I can tell. And the way they usually lock out old machines is by the restore disc. But it's Apple and while they often control things, they are inconsistent. So for all I know they went to the extra trouble to make old Snow Leo discs unbootable on Mac Pros -- sure sounds like it -- it's just unusual, even for Apple!

Good luck, have fun 😉

I did do parts a5-a9. I was just asking if it made a difference which computer the combo updater was downloaded on. I had already downloaded all the necessary apps and updater. However i'm doing it gain and making notes and taking screen grabs. Hope to post all that soon.

If you are going to downgrade lion you must do this first as a backup unless you decide to keep your recovery partition but for double backup safety i case your system has a HD failure:

Download Lion Recovery Assistant from Apple Support Downloads:

http://support.apple.com/kb/index?page=answerlink&url=http%3A%2F%2Fsupport.apple .com%2Fkb%2FDL1433&answerid=16777216&src=support_site.downloads.search

STEPS:

1. Plug in your lion system, boot, go through inital set up and get to the desktop

2. Download and install lion recovery assistant

3. Plug in a usb flash/thumb drive at least one gig i recommend 4-8

4. Dbl click th LRA and run it and follow instructions

5. Once it is complete you are done

6. Eject the thumb drive and keep it safe.

When you need to use it just plug it into a usb port restart the system holding down the option key and select Recovery HD. Once loaded you can do whatver you could do with the lion parition

Cool! Sounds like 10.6.8 v 1.1 update didn't "take" the last round 😉 But it'll work this time! Woot.

Thanks so much for posting the Lion Recovery instructions... it's too bad this discussion forum doesn't let us edit posts.... we could consolidate this into a guide with the proper links and updates....

0) Referral to a thread that details a successful Target Disc Mode method [I don't have one]

1) Backing up your Lion Recovery

2) Disclaimers and verified success

3) Updated Roy method (with pictures!)

The Lion Recovery thumb drive instructions gives you a backup to install lion in case your HD fails and you don't need the Apple USB Thumb Drive for $69. In fact i read on one of Apple's sites that if you use the the $69 Apple thumb drive to install Lion it does not create a Recovery HD partition on the system just installs Lion and you can then only use the $69 thumb to reinstall. So creating your own is the best way to do it. When you do go to install Lion from the Recovery partition whether on your system or thumb drive, it apparently checks in with Apple for authorization before letting you do so. The other OCD option is to make an image of your lion system before setup by booting using a bootable clone or TDK mode. This way you can use Disk Utility to restore but i think the thumb drive is enough.

I noticed something different this time around and i am documenting everything and taking screen grabs and will post that soon. The key is to pull the combo updater package out to your working space and not drag and drop the white mounted icon or the .dmg file without mounting into post installer scripts window. Pictures coming soon. Crossing my fingers. What we could do once everything is posted is copy and paste it in one new posting and i might be able to put a pdf together. This time around is seems much easier and less complicated.

I can write up target disk mode instructions but using the word successful is misnomer as the system you get ends up offering half the performance based on geekbench scores. So you can install SL using TDK mode or even creating a bootable clone with all the updates from that TDM method but i believe the machine you use TDM mode in makes a difference. I believe using an identically and equally in every way matched system using the TDM method works best for example if you are downgrading a core i7 imac then it would be great to have an imac with SL on it that also was core i7 with exact same config for TDM method. But that would be pointless because if you had a matched system you could just create a .dmg image of it and restore it on your system. So the TDM will work but you will not get the full performance. My first roy attempt basically resulted in the tdm method without having to do TDM. So in short TDK Method = My First Roy attempt and neither provided full geekbench scores.

Well the geniuses at the store seem to know what they're doing. They loaded their SL 10.6.8 network disk image onto the computer after wiping the drive and it loaded up just fine. No version of Snow Leopard under 10.6.8 will run on new Mac Pros. I say that as of Sept. 10 2011.

Hope this helps somebody else out there! Thanks guys.

@Photonomadic

Did the Apple Store give you any grief? What did you say? Run geekbench, its free for the32 bit version and compare it to their benchmark for your system and report it here please. Or just download geekbench, install and run. Make sure nothing else is running. It will give you a final score at the top. Just report that number here.

@Tech Harmony, Roy and all

Okay so my second attempt at roy's method restore file was successful. The final restore file was 5.26GB and it did install 10.6.8 fine. However........

I ran software update and ran geekbench. The score was the same low 55xx. It should be 10179

So from my experience TDM method=Roy's Method with the same low performance scores. So either Apple has done something in the firmware to neuter the system or the roy installer/TDM method lacks core i support or there is a bug in the geekbench 2.2 software. Nearly all of the geekbench benchmarks i have seen used 2.12 which i can't find anywhere to download. I have a call in to the geekbench guys.

So now my only options are the system restore disk or taking it to Apple. My system is a late Aug 2011 CTO build core i7, 2.8 Ghz, 21.5", 2TB HD, 4GB RAM system

Thank you for doing all that @zirkenz. Truly epic!

I'd be curious about the results of an Xbench test.

System Profiler will show you how your RAM, HD, processor, etc. post up

Activity Monitor (set to show all processes) can give you a sense of the processes running ... I sort it so the most intensive CPU processes are at the top. There are also little graphs depicting how your memory is being used.

Something like MenuMeters will show you a view of each of your cores/threads and how hard they are working...

You can try booting into Safe Mode and running Geekbench....

But it sounds like your next step would be re-installing Lion (or installing Lion to a bootable external drive) so that you can see if your Geekbenches are working alright under Lion.

Usually if OSX doesn't like the machine it's running on, it won't even boot or it will kernel panic almost immediately. It's amazing to me that Apple would cripple the ability of its own software to run on its own compatible machines while others are getting OSX to run fantastically on machines it was never designed for. Is this Apple intentionally controlling how its computers are run to a whole new level? An automatic leftover from a habit of control? Or is it really some other problem (e.g. hardware)?