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Possible Duplicate:
How to setup Windows from an external hard drive?

I want to install an OS (Mac OS X, Windows 7 or 8 beta) from my external HDD, since I don't have any USB sticks or DVDs, but I have 5 blank 2.5" external HDD.

Is this possible? I just can't think of any solutions.

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marked as duplicate by Ƭᴇcʜιᴇ007, 8088, RedGrittyBrick, studiohack Nov 18 '11 at 4:29

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

@techie007 the other question is for PC, this is for a Mac. – Dustin G. Sep 17 '11 at 4:58
@Dustin G. Since the question doesn't say the user wants to install it to a Mac specifically, it's a 'possible' dupe in my mind. Perhaps the user (or yourself) should edit the question to make it more specific to what they are actually trying to achieve. – Ƭᴇcʜιᴇ007 Sep 17 '11 at 15:45
@techie007 you are correct, I assumed he meant on a mac when he mentioned putting MacOS on the machine, but it's possible me meant for hackintosh purposes. I suspect that is so since he has not responded. – Dustin G. Sep 17 '11 at 22:52
up vote 3 down vote accepted

Yes it is possible.

All you need is the external drive and an ISO of the operating system you want.

  1. Open Disk Utility (Utilities folder in the Applications folder)
  2. In the left pane of the window, you will see your USB drive - select it.
  3. In the right pane, select the Partition tab
  4. You will see the partitions of the drive (probably only one), select the plus sign below the partition map.
  5. Once the new partition appears, you can drag the top boundary of the partition in the map until the size of the partition is a little bigger than your source Windows or OS X ISO file.
  6. Select Apply (lower left of screen)
  7. Now under your drive in the left pane, you will see the new partition - select it.
  8. Looking at the right pane again, you will want to select the restore tab.
  9. With the restore tab open, you will have 2 boxes - one that says Source and another that says Destination.
  10. To the left of the Source box, there is a button that says Image... click this button and in the resulting window, navigate to the ISO / Disc image that you would like to use for installation and hit the Open button.
  11. For the Destination box - you can drag the icon for the partition that you want the OS disk on from the left pane into that box.
  12. Once both the Source and Destinations are correct, click the Restore button.
  13. You now have a Hard drive with a bootable partition to start the OS X or Windows installer.
  14. Reboot, and before / during the chime sound, hold down the option key.
  15. Of the bootable devices that appear, you should see your main HDD and now the partition that you use made.

Have Fun!

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