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installing osx on an external drive

806 Views 15 Replies Latest reply: Oct 12, 2013 9:39 AM by MlchaelLAX RSS
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tedp1 Calculating status...
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Oct 6, 2013 7:53 PM

Hey all,

I bought an enclosure, installed a sata drive that I didn't install an os on years ago but used for capturing video.  I would like to install osx5.8 and then x.6 on it so I can install FCS 1 on it and capture video again.


I've got the drive usb 3 connected to my macbook pro, how do I get the operating system on it without erasing any of the footage I've got on it?


Another thing, the 5.8 disks are from a macbook that is no longer functional.  Will those disks even work?





  • Tlix Level 4 Level 4 (1,315 points)
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    Oct 7, 2013 12:21 AM (in response to tedp1)

    Installing the operating system onto the drive shouldn't delete anything from it.


    However you need to make sure that the drive is in the right format. It will need to be using GUID and have a Mac OS Extended (Journaled) partition. Be aware that trying to repartition the drive WILL delete the data on it though.

  • OGELTHORPE Level 7 Level 7 (22,505 points)
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    Oct 7, 2013 4:44 AM (in response to tedp1)

    If you have used this external HDD before, it probably is already formatted correctly.  To make certain, when connected to the Mac, click on the Icon (COMMAND I) and see what the resulting display shows in the format field.


    If you want to install Snow Leopard on that external disk, you will have to get a retail copy from the Apple online store:




  • OGELTHORPE Level 7 Level 7 (22,505 points)
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    Oct 7, 2013 6:39 AM (in response to tedp1)

    Did you check the format per my suggestion?


    Screen Shot 2013-10-07 at 9.32.29 AM.png

    If the Snow Leopard disk is a gray one, it will only work if it is the original installation for that specific Mac model.  If it is not, then you need a retail disk as shown in my link. 



  • Kurt Lang Level 7 Level 7 (31,485 points)
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    Oct 7, 2013 8:15 AM (in response to tedp1)

    One thing you will likely have to do since the disk originally came from a G5 is repartition it with Disk Utility so you can change the drive map from Apple Partition Map to GUID.

  • Kurt Lang Level 7 Level 7 (31,485 points)
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    Oct 8, 2013 6:31 AM (in response to tedp1)

    The format and the partition map are two different things. Put the disk from the G5 into any open bay of your Mac Pro (with the computer turned off, of course). Open Disk Utility and highlight the G5's drive. At the lower right, it will show what the current partition map is. Example:


    Screen Shot 2013-10-08 at 8.15.11 AM.png


    Mine notes GUID Partition Map. If yours comes up as Apple Partition Map (and it likely will), you'll have to repartition the drive.


    You will lose everything on that drive in the process, so make sure you've backed up any data you need to save, first.


    After highlighting the physical drive in Disk Utility as shown above, click on the Partition tab. The drive layout graphic will default to "Current". Even if the entire drive is one partition and you still want it to be one, you must still change Current to "1 Partition". When you do that, the Options button below the graphic will now be active. Click that and change the radio button choice to GUID. Save the changes and then click the Apply button.


    At that point, you may as well do you cloning, too. Click on the Restore tab. You just drag and drop what partition you want to duplicate to where. Here, I'm telling Disk Utility to clone whatever's on the drive Mac Pro to Video:


    Screen Shot 2013-10-08 at 8.27.28 AM.png


    Assuming your current drive already has Snow Leopard, FCS1 and your other software on it, you'll be done. The old drive will be an exact duplicate and you can boot to either. To clear the original, smaller drive, restart and boot to the duplicated drive. Then erase the original.

  • Kurt Lang Level 7 Level 7 (31,485 points)
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    Oct 9, 2013 6:32 AM (in response to tedp1)

    Oops! Sorry, misread your Mac model. But yes, the procedure is the same. Your main drive will end up duplicated on the external.


    You can boot from the external and run your OS and apps from there all day long, but it will be quite a bit slower. USB or FireWire can't transfer data anywhere near the same rate as SATA.

  • Kurt Lang Level 7 Level 7 (31,485 points)
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    Oct 9, 2013 7:32 AM (in response to tedp1)

    Okay, we need to back up a bit. Did this MBP come with Mountain Lion? If so, you can't run Snow Leopard at all. At least, not as a bootable OS. You'd have to purchase Parallels or VMware software, install Snow Leopard Server in the VM (virtual machine) software, and then your PowerPC apps. So you'd end up with Snow Leopard running concurrently within Mountain Lion. There is no other way. Snow Leopard Server can be purchased directly from Apple for $20.

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