Can (and should) I run an iMac off an external drive?

Discussion in 'iMac' started by NJRonbo, Sep 7, 2013.

  1. NJRonbo macrumors 68000

    Jan 10, 2007
    Have a friend who is an iMac owner. I believe it is a 2007 iMac. It shipped with Leopard but has been upgraded to Mountain Lion.

    His internal drive just took a dump. He is contemplating taking the iMac over to the Apple store and just having them put a new one inside....

    ...but at the same time an option is being brought up as to whether it would be better just to purchase an external hard drive and run the iMac off of that?

    So, the questions are....

    1. Can you run an iMac off of an external drive and would it be just as fast as the internal?

    2. What would be the procedure for installing the Operating System into that external hard drive?

    Bottom line...need to know if running off an external is a smart move or is it just better to go to the Apple Store and pay them to put a new internal into the iMac instead.

    Thanks, in advance, for the assistance
  2. simsaladimbamba

    Nov 28, 2010
    Yes, you can.
    Best use a Firewire 800 enclosure for 3.5" S-ATA drives for that and get any HDD you like, or just get one of the Firewire 800 HDDs available.

    USB 2.0 will also work, but is a lot slower.

    As for replacing the HDD yourself, have a look here (the second row has the four 2009 models).
  3. McGiord, Sep 7, 2013
    Last edited: Sep 7, 2013

    McGiord macrumors 601


    Oct 5, 2003
    Dark Castle
    Yes, you can run your Mac with an external HDD. You only need to install Mac OS X in the external drive.
    Also you can also connect to the internal HDD booting from another Mac and having it connected in target disk mode.

    And before going to the Apple store check if you would prefer to open the iMac yourself and swap the internal HDD by yourself. You can try putting it in an external enclosure and using another Mac to check it, recover your data.

    Also don't you have a backup HDD???
  4. jamesjingyi macrumors 6502a


    Dec 20, 2011
    As for installing OSX, just run the installer from the disc he has or redownload the installer and select the drive he has. Imho I would install a new drive myself into the iMac because its just a safer and more convenient option and would (probably) be faster.

    Oh also just in case this helps, when you get a new drive, you could just verify and repair the disk... That sometimes works with sorting out problems (as it has before) on my old Black MacBook. I would however steer clear of using it for the internal drive or for anything important and as maybe a second time machine.
  5. Fishrrman macrumors G5


    Feb 20, 2009
    [[ 1. Can you run an iMac off of an external drive and would it be just as fast as the internal?]]

    Yes, you can.

    Your friend should consider a USB3 enclosure, or (better yet) a USB3/SATA "docking station".

    Since your friend has a Mac with USB2 (not USB3), booting times will be slower than from the internal drive. HOWEVER -- once up-and-running, chances are your friend will not notice much (or any) difference in "real world running speeds".

    I have a 2007 iMac that I boot and run from a USB2/SATA dock for music production. Works just fine.

    2. What would be the procedure for installing the Operating System into that external hard drive?

    I suggest you do this on _your_ Mac (if you have one).

    It would help if you tell us WHICH Mac you have, and what OS you are running.

    It's possible that you could do a "clean install" to the external drive on YOUR Mac, then take it to HIS Mac, and get booted that way. This may not work in all instances, but it CAN work in some. It's worth a try.

    Just wondering -- have you tried connecting HIS iMac to YOUR Mac in target disk mode?
  6. NJRonbo thread starter macrumors 68000

    Jan 10, 2007
    It would be difficult for us to pair our Macs.

    I can tell you that he has a 2007 iMac with original Leopard install disc.

    He is definitely looking to use an external drive now that all of you have confirmed it can be done.

    So, any further tips you want to provide would be most appreciated.

    He is going to be doing the install shortly. Already told him to format the external drive in Mac OS Journal.

    One more thing I forgot to mention...

    He has a Time Machine backup.

    So, eventually, once he installs his operating system (Leopard) and then does the upgrades back up to Mountain Lion, he is going to do a Time Machine restore to get all his files back.

    All this seem logical? Want to make sure he is doing it the right way.
  7. ElectronGuru macrumors 65816

    Sep 5, 2013
    Oregon, USA
    My 08 iMac HD bit the dust last year. Bought an SSD (intel I think), installed it into a portable FW800 chassis, plugged it into the back. Made a 10.8 install DVD from the Macworld instructions, did a clean format + install. During initial boot, told it to restore from time machine (from external USB drive). Came back when it was done and restarted.

    Everything was like it was, except the speed. Holy cow, the SSD boost was almost like getting a new computer. If I could go back to years before the crash, I would do it just for that. FF a year and everything is still solid and fast (granted its still a 5 yo computer). The SSD just hangs out the back.

    Highly recommended.
  8. psingh01 macrumors 65816

    Apr 19, 2004
    Sounds right to me. I think there are even steps during the OS X setup that asks if you want to do a time machine restore so its really simple.

    Also I think the mountain lion installer is the full installer (even though its called an upgrade). There are ways to make a DVD of this so if you do that ahead of time you save the trouble of upgrading from leopard.
  9. NJRonbo thread starter macrumors 68000

    Jan 10, 2007

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