Mar 12

osx installer

It’s very handy to have a bootable version of OS X on a thumb drive.

I have written how to do this using a program called DiskMaker X,  and I have written about how to do it from the command line here,  but after doing this a few times I find the most reliable method is the one outlined below.   It uses Apple’s built-in disk utility.This works with any version of OS X. Mountain Lion, Yosemite, El Capitan etc. You’ll need an 8G USB thumbdrive.

1. Purchase or download the OS X Installer via the App store. It will look something like this:


2. Right-click on the installer and select “Show Package Contents. ”  Open the ‘SharedSupport’  folder and find  the file called  â€œInstallESD.dmg”.

3. Insert the thumb drive and use disk utility to format it as Mac OS Extended (Journaled) with GUID Partition Table.

4. Use Disk Utility to ‘Restore’ the dmg file to a thumb drive. Select the thumndrive in disk utility and then go to the ‘Edit’ Menu of Disk Utility and select ‘Restore.’ It will prompt you for a disk image. Select the ‘InstallESD.img’ file.

This will make an OS X Installation USB drive like you buy from the Apple Store.


One Response to “How to make a bootable Thumbdrive of OS X”

  1. matthias says:

    Hi does the disc utility method work with installing el capitan on a snow leopard mac? are there specific instructions what to do after making the bootable drive then attaching it to other computer? I tried it and the smaller packages load onto the hard drive but the mpkg doesnt recognise the native drive,

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