Installing Snow Leopard on 2nd partition?

Discussion in 'macOS' started by Saturn1217, Aug 27, 2009.

  1. Saturn1217 macrumors 6502a

    Apr 28, 2008
    Hi all,

    I apologize for the noobish question but I was wondering if the following were possible.

    From what I've read it is possible to partition your hard drive so you can have leopard and snow leopard installed at the same time on one computer, correct?

    Can I partition my current drive without having to reinstall leopard? or lose any data? I will of course have a back up but is it possible to create another partition if I have room while keeping my leopard install intact?

    If later I decide I love (or hate) snow leopard can I get rid of the other partition and expand one of the partitions to take up the entire hard drive (like how I have it now) again without reinstalling or losing data? (on the partition I intend to keep not the one i get rid of obviously)

    Just wondering because I just moved to the mac like 2 months ago and despite what everyone said the transition wasn't really so smooth (mainly because I like to tweak things but don't really understand computers well enough to do this properly) I have everything on my computer set up now exactly how I want it so I was going to wait until like 10.6.3 or something but with all the reviews coming in well...I am getting a bit curious about snow leopard and would like to try it out.

    Thanks in advance for answering probably very obvious questions :eek:

    PS I searched both mac forums and google for like 30 min before posting this thread so go easy on me!
  2. RemarkabLee macrumors 6502a

    Nov 14, 2007
    Yes you can.

    Fire up disk utility and click on your primary hard disk, then add a partition as the default HFS+ journalling and give it a label 'Snow Leopard'.

    Pop in the Snow Leopard DVD and restart. During the install process, make sure you select 'Snow Leopard' volume as your destination and your good to go.

    When restarting your Mac, hold the Option/Alt key down at the start bong and hold it down until you see the startup disk selector, so you can choose to boot from Leopard, or Snow Leopard :)
  3. lappinit macrumors newbie

    Aug 28, 2009
    I am in the middle of doing what the thread starter wants to do, but I'm having problems...

    I made a (3rd) partition of 50GB on my Mac HD (the other one being Windows XP), named it Snow Leopard, and rebooted from my 10.6 upgrade disc.

    However, the installer did not see the newly created partition.

    I booted back into Leopard, and in disk utility I now seem to have a "phantom" partition - invisible, but my Mac HD seems to be 50GB "heavier" than it was...

    Any ideas?
  4. RemarkabLee macrumors 6502a

    Nov 14, 2007
    Was 50Gb enough? Perhaps there is a minimum partition size required... At any rate, I do not know why the partition didn't create correctly... Bear in mind however, if you add a third partition, Windows may stop working as the partition ID may change - it did in my case. The Bootcamp partition went from the second partition to the third partition, so Windows failed on the HAL.DLL point. Possibly repairable in safe mode and change the relevant registry section....

    It is probably easier to just boot using the SN DVD, and use Disk Utility within the SN installer (from the menu), make changes, then you can tell if SN can see the new partitions, thus saving the need to reboot everytime.
  5. lappinit macrumors newbie

    Aug 28, 2009
    Thanks for the quick reply. I'm not at home to check bootcamp, but it sounds like I've made some extra work for myself...
  6. Saturn1217 thread starter macrumors 6502a

    Apr 28, 2008
    thanks for the reply,

    I guess the concept seemed simple enough so I was curious why no one else seemed to consider this option if they were afraid of snow leopard breaking app compatibility etc.
  7. Fishrrman macrumors G5


    Feb 20, 2009
    RE: Installing Snow Leopard on 2nd partition?

    "From what I've read it is possible to partition your hard drive so you can have leopard and snow leopard installed at the same time on one computer, correct?"

    Yes, I just did this for a friend a couple of days ago.

    Here's what to do:
    1. First check your existing partition. You want to be sure the drive has enough "empty space" with which to create a _new_ partition to install SL onto.

    2. Assuming there is enough space (I would reckon the minimum would be about 30gig, but I have SL running smoothly at the moment on a partition that's only about 17gig!), launch Disk Utility.

    3. In DU's left window, click the "topmost" representation of your internal drive.

    4. Click "partition". You should get the window with the rectangular depiction of your disk.

    5. Choose "2 partitions". DU should now display 2 volumes.

    5. Grab the "dividing line" and drag it to size the soon-to-be-created partition to the size you wish. I will _guess_ that DU "reserves" a certain amount of space for the files of the existing (single) partition, plus some "free space" on top of that. In other words, you can't create a new partition that would take up more free space than is currently on your drive.

    6. When you have the partition sized where you wish, click "Apply" down below.

    7. It will take a few minutes for DU to do its thing. I'm guessing that before DU actually "divides" the drive's directory, it does some adjusting and moving (if necessary) of the files already on the drive. This "cleans up" the physical sectors where the new partition will go.

    8. When done, you should now have _two_ volumes that appear on your desktop. One is the "old drive". The other will be the new one, as-yet with no files on it.

    9. I'd suggest a "test boot" from the old volume, just to make sure it starts up, that everything looks right to you, etc., before going further.

    10. When you're confident the old volume is fine, boot from the Snow Leopard DVD and choose to install to the NEW [empty] volume.

    11. When done, you should have TWO bootable volumes - your old one, and the new SL. You can choose which to boot from using the Startup Disk preference pane. Or, even easier - hold down the option key when you start up and keep holding it down until the Startup Manager appears. You'll see what to do!

    12. When the time comes that you feel confident you no longer need your old System, you can either do a SL install "over" the old system (on the old partition), or - another way to do it is to be sure that your new SL volume is the way you like it, and "clone it over" to the older partition using SuperDuper.

    13. When all is said and done, I'd recommend keeping that second bootable partition around. It's ALWAYS preferable to have a second volume close-at-hand that you can start up from in an emergency!

    - John

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