How to Install Mac OS X Using A Removable USB Drive
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Want to put the OS X installer onto a bootable flash drive? Apple doesn’t provide an official tool to create bootable copies of their operating system, outside the recovery partition, but a third party tool called DiskMaker makes for a relatively painless process.

Why would you want to do this? Lots of reasons, including if:

  • You plan to replace your Mac’s hard drive, so the restore partition isn’t an option.
  • You’re building a Hackintosh How To Build Your Own Hackintosh How To Build Your Own Hackintosh This "How to Hackintosh" guide outlines what you need to do in order to build a power PC Hackintosh. This guide shows you the way. Read More .
  • You need to install/upgrade OS X on a computer without broadband access.
  • You want a way to install OS X in case of total hard drive failure.

To get this working you will need: a flash drive with at least 8 GB free, a currently operational Mac, and access to broadband Internet. Let’s get started!

Step 1: Download Your Chosen Version of OS X

The first thing you need to do is download the installer for whatever version of OS X it is you’d like on your flash drive. The only (official) way to do this is using the Mac App Store – I’m personally downloading El Capitan OS X El Capitan is Here! Upgrade For A Smoother Mac Experience OS X El Capitan is Here! Upgrade For A Smoother Mac Experience Mac OS X El Capitan is a subtle release: its biggest changes aren't visible — but you'll probably notice them anyway. Read More .


You can always find the version of OS X installed on your Mac, and newer versions of OS X, in the App Store by searching. If you’re looking for an older version of OS X, you can find it in the Purchased tab (assuming you’ve downloaded it before).


Once you’ve started the download, you can monitor its progress over on the Purchased tab of the Mac App Store. Versions of OS X are typically sized between 6-7 GB, so the download is going to take a while.


Whatever version of OS X you download, do not follow the installation instructions when the download completes – just close the window and move on to the next step.

Time Machine Users: Potentially Avoid Re-Downloading

Re-downloading OS X might take a long time, especially if the Mac App Store is misbehaving (which, let’s face it, happens a lot). The OS X installer deletes itself after upgrading, which is why you need to re-download the installer to make a thumb drive.

But there’s a potential workaround if you back up your Mac regularly The Ultimate Triple Backup Solution For Your Mac [Mac OSX] The Ultimate Triple Backup Solution For Your Mac [Mac OSX] As the developer here at MakeUseOf and as someone who earns their entire income from working online, it's fair to say my computer and data are quite important. They’re set up perfectly for productivity with... Read More . You hopefully ran a backup before upgrading your OS, and that backup probably includes the downloaded OS X installer.

How to Install Mac OS X Using A Removable USB Drive osx installer time machine

Check the Purchases tab in the Mac App Store and note the date that you downloaded OS X. Now head to your Time Machine disk in Finder, and browse to the date you just found – then head to the Applications folder within the backup. You should be able to find the installer, as shown above. Just drag that file to your Applications folder, or anywhere you’d like.

Step 2: Install Diskmaker

The next step is simple: head to and grab the latest version of DiskMaker. This free program makes creating a bootable OS X drive simple. Do the usual drag-and-drop-the-icon-dance to install the software.

Step 3: Run Diskmaker

Now the real magic beings: fire up Diskmaker (if it won’t load, check your Gatekeeper settings What Is GateKeeper & How Does It Help Protect My Mac? [MakeUseOf Explains] What Is GateKeeper & How Does It Help Protect My Mac? [MakeUseOf Explains] Will your favorite programs ever run again? Certain programs won't load anymore - a message about Unidentified Developers shows up instead. There isn't even an obvious option to run the app. Gatekeeper just might be... Read More ). You should be prompted with a choice:


Pick which version of OS X you hope to install from your drive. You’ll then be prompted to pick your drive:


It’s really important that you pick the correct drive, because everything on that drive is going to be deleted – pay attention.


Once you’ve gone through all of the steps, DiskMaker will do its thing – eventually it will ask you for your password, so don’t walk away until you’ve done that.

Step 4: Boot From External Drive

When your drive is done, booting from it is simple. Power your Mac down, then hold the Option key as you turn it on. You should see a selection of drives:


Just pick your drive, and eventually the OS X Installer will open.


You can now install OS X, or use any of the utilities that come with the installer.

Alternative: Install OS X to an External Drive.

Maybe you don’t want to install OS X from a USB drive, but actually boot the entire operating system from a USB drive. Good news: that’s possible.

We’ve outlined how to do this in the past How To Install OSX Lion On An External Drive To Test It Out [Mac] How To Install OSX Lion On An External Drive To Test It Out [Mac] One of the great things about Macs is that the OS is bootable on any Mac machine, regardless of which computer it was originally installed on. This means that if your desktop breaks, you can... Read More for older version of OS X, but these days Apple themselves offer official instructions for the job, and it’s really simple: just connect an external drive, boot your Mac into recovery mode, then pick your external drive as the installation medium.

Boot Windows or Linux From a USB Key

How to Install Mac OS X Using A Removable USB Drive mac boot linux running

Of course, OS X isn’t the only operating system your Mac can run: you could also get Linux or Windows running on it. We’ve shown you how to boot a Linux live USB key on your Mac How to Create and Boot From a Linux USB Drive on Mac How to Create and Boot From a Linux USB Drive on Mac There are a few ways to get a create a live Linux USB drive that will boot on your Mac: you can do it with freeware, or get your hands dirty with the command line. Read More , and there are several ways to boot Windows on a Mac 4 Ways To Get Windows On Your Mac 4 Ways To Get Windows On Your Mac Want Windows 8 running on your Mac, but don't know where to start? Let us show you how. Read More . So if you want something besides OS X and your USB key, you’ve got options.

USB Installation is Great

I plan on partitioning an external hard drive, with one partition capable of installing OS X and the other holding various software installers. With that I should be able to recover from a hard drive failure pretty quickly.

I want to know what you’ll be using your bootable OS X key for. Let me know, along with any questions you have about the process, in the comments below.

Explore more about: Install Software, OS X El Capitan, OS X Mavericks, OS X Yosemite, USB Drive.

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  1. Wiley1
    May 11, 2018 at 3:37 pm

    The experience of building the USB with DiskMaker_X_7 was painless. I am now able to boot to a screen with two icons like the one shown in this article. At this point, I select the USB drive that is named "Install OS X High Sierra" and that takes me to the menu with 4 choices. When I go into Disk Utilities, I am able to re-format the 500GB HD in the iMac and it automatically creates a new volume. I named my volume "Abyss".

    Then I return to the 4-choice menu and select "Install MacOS", and click the Continue button. The Continue button turns gray -- forever.

    Yes, I have verified that this iMac is eligible to use High Sierra.

    What could be wrong? Is it possible that I need a newer OS X Base System? Can that be upgraded?

  2. Mohamed
    June 20, 2016 at 8:10 am

    Cant boot my iMac, only in recovery mode...and reinstalling OS X from the web is a headache since my internet connection is slow and unstable....Creating USB bootable right now, fingers crossed! thanks for the help

  3. kong
    May 14, 2016 at 3:13 am


    I have the same problem which is why i search and get to here. Seem that USB bootable os can help. Anyone can help to answer Nazy.

  4. nazy
    May 10, 2016 at 10:46 am

    My mac is not working and I cant log in, and i have low storage to reinstall osx using recovery system.and i have tried others way but it didnt help. so I want to know if I download El capitan using another computer, which is not a mac,and also from the sites that have a link for downloading, what else should i do, to be able use it as a start up disk on my mac ?

    pleeeeease help!

  5. Anonymous
    October 29, 2015 at 5:58 am