Create a MAC OS X Installation USB

The following steps will show you how to install Mac OSX from a USB drive.

You will need:

  • 1  USB ( At least 16 GB)
  • A Mac OS X Disk Image (.DMG file)
  • 7 Zip (Used to extract the files you will need)
  • TransMac (Used to create an image on your USB drive)

The first thing we need to do is to get to a file called “InstallESD.dmg”.  This is the actual image that we are going to put onto the USB.  You can get this file from an actual installation disk or from a .dmg file that you downloaded previously.  The .dmg file that you download may have various names so don’t worry about what it is called.  Also, if you did download the file from a torrent site please be sure that you are using a clean file and don’t get yourself infected with malware.

  1. Locate your “Mac OSX.dmg” file.
  2. Right click and select “Open With”; Select 7-Zip        (Install 7-Zip if you didn’t already)
  3. Open the folder named “InstallMacOSX.pkg”
    Inside this folder you will see a file names “InstallESD.dmg”
  4. Highlight the “InstallESD.dmg” file and then click the “Extract” button that is just above it.
  5. Select a destination for the file to extract to.  I recommend just putting it on the desktop.  Press OK.

You should now have a file on your desktop (or wherever you extracted to) named InstallESD.dmg.  the next steps will have you prepare your USB drive and then save the image to the USB.

  1. Open “My Computer” or “File Explorer” so that you can see the USB Drive that you want to use.
  2. Right click on the USB Drive and select “Format”
  3. Press “OK”.  It shouldn’t take very long.

Now our USB Drive is prepared.  The next steps will have you save the InstallESD image to the drive.

  1. In TransMac, right click on your USB Drive.  Select “Restore with Disk Image”
  2. If you are sure that you chose the right disk then select “Yes” on the warning screen.
  3. At the next window, choose the file from the desktop (or wherever you saved it) named “InstallESD.dmg”
  4. Press “OK”This will take a few minutes to complete.

Once it is done you should be able to use the USB to boot and install Mac OS X.  You can boot into the USB by holding the “Option” button on your Mac immediately after powering it on.  Once you see the icons on the screen you can release the option button.  Select the USB Drive and it will boot into the installation.