How to make a bootable Mavericks install drive

Mavericks (OS X 10.9) doesn’t ship on a disc. Instead, it’s available only as an installer app downloadable from the Mac App Store, and that installer doesn’t require a bootable installation disc. But there are a good number of reasons you might want a bootable Mavericks installer on an external hard drive or a thumb drive (USB stick).

For example, if you want to install Mavericks on multiple Macs, using a bootable install drive can be more convenient than downloading or copying the entire installer to each computer. Also, if your Mac is experiencing problems, a bootable install drive makes a handy emergency disk. (The OS X Recovery feature is a big help here, but not all Macs have it—and if your Mac’s drive is itself having trouble, recovery mode may not even be available. Also, if you need to reinstall Mavericks, recovery mode requires you to download the entire 5.3GB installer again.) Finally, if you need to install Mavericks over Leopard—assuming you have the license to do so—a bootable install drive makes that process easier.

Thankfully, it’s not too difficult to create a bootable install drive from the Mavericks installer. I show you how, below.

If your Mac came preinstalled with Mavericks

If you own Mavericks only because you bought a Mac that shipped with Mavericks preinstalled—in other words, you never purchased the OS from the Mac App Store—use our instructions for creating a bootable Mavericks install drive for newer Macs, instead of the instructions here.

Get the latest version of the Mavericks installer

Before you make a bootable install drive, you should make sure you have the latest version of the Mavericks installer. What? You didn’t even realize that there are different versions of the installer? It turns out that when you download an OS X installer from the Mac App Store, that copy of the installer contains whatever version of OS X was available at the time of download. For example, if you downloaded OS X 10.9 on the day Mavericks was released, you downloaded the 10.9.0 installer. A bootable install drive you create from that installer will install OS X 10.9.0.

However, Apple regularly updates the OS X installers it makes available for download from the Mac App Store. For example, when the inevitable 10.9.1 update is released, a few days later the Mac App Store will begin providing an updated Mavericks installer that installs 10.9.1 right off the bat. Using the latest installer for your bootable install drive is convenient, because it means that if you ever need to reinstall Mavericks, you won’t have to install 10.9.0 and then immediately install the latest big update.

Obviously, then, you want to create your bootable install drive using the latest version of the Mavericks installer. However, unlike with other Mac App Store-purchased software, the Mac App Store does not update the copy of the Mavericks installer app sitting on your hard drive. If you’ve got an older version of the installer and you want the latest version, you must delete your current copy of the installer and then redownload the Mavericks installer from the Mac App Store. (If the Mac App Store won’t let you redownload the installer, quit the Mac App Store app, relaunch it, and then Option+click the Purchases tab in the toolbar; that should show the Download button next to Mavericks in the Purchases list.)

Similarly, any bootable Mavericks install drive you create will not be updated to the latest installer version automatically. So if you create an install drive and later download an updated version of the Mavericks installer, you’ll want to erase that install drive and recreate it using the new installer.

How do you know if you have the newest version of the Mavericks installer? The easiest approach is to look at the Information box on the Mavericks page on the Mac App Store—specifically, check the date next to Updated (or Released, as the case may be immediately after the initial release). Then locate your downloaded copy of the Mavericks installer in the Finder, choose File -> Get Info, and look at the date next to Modified. If the Mac App Store date is newer than the Modified date on your copy of the installer, you need to redownload the installer to get the latest version. (The version listed in the Mac App Store’s Information box is the version of OS X you’ll get if you download the latest installer.)

Note: As I explained in our main Mavericks-installation article, if you leave the Mavericks installer in its default location in the Applications folder when you install OS X 10.9, the installer will be deleted automatically after the installation finishes. So if you plan to use that installer on other Macs, or—in this case—to create a bootable drive, be sure to copy the installer to another drive, or at least move it out of the Applications folder, before you install. If you don’t, you’ll have to redownload the installer from the Mac App Store before you can create a bootable install drive.

A note on installer compatibility

The initial Mac App Store version of Mavericks will boot only those Macs released prior to Mavericks’s debut; Macs released after Mavericks’s debut ship with a newer version of OS X 10.9 preinstalled. This means that if you made a bootable install drive immediately after Mavericks was released, and then later bought a new Mac, your install drive won’t boot that Mac (though it will boot any older Macs you own).

However, as explained above, Apple regularly updates the OS X installer on the Mac App Store so that it installs the latest version of OS X 10.9. If you create a new bootable installer using the first major update to Mavericks after your Mac was released, that drive should be able to boot all your Macs.

What about an optical disc? You may have noticed that I didn’t mention making a bootable install disc (DVD or CD). Though you can do it, I don’t recommend it. More and more Macs ship without a built-in optical drive; booting and installing from a DVD is very slow; and 8GB flash drives can be found for $10 or less. All of this means that there’s little reason to opt for a DVD anymore. In addition, whenever an update to OS X is released, you can easily erase your bootable USB stick or external hard drive and update it to contain the latest OS X installer; with a DVD, you have to toss the disc in the trash and start over, which is both a hassle and bad for the environment.

All that said, if you’re absolutely convinced that you need an optical disc, Thomas Brand explains how to create a Mavericks recovery CD. The resulting disc won’t contain the full installer; rather, it’s a CD version of OS X Recovery. This means that when you install Mavericks using the disc, the installer needs to download roughly 5GB of installer data on the fly—which means that installation will be even slower.

Create the Mavericks install drive: The options

There are three ways you can create a bootable OS X install drive: using a new feature, called createinstallmedia, built into the Mavericks installer itself; using Disk Utility; or using the third-party utility DiskMaker X, which, despite its name, also works under Mavericks. (For OS X 10.7 and 10.8, you also had the option of using the third-party utility Carbon Copy Cloner. However, because of changes in Mavericks, the developer of Carbon Copy Cloner has removed this feature. I’ll update this article if Carbon Copy Cloner becomes an option again.)

Using the new Mavericks feature for creating a bootable drive, createinstallmedia, is the easiest method, and it’s the one that I recommend most people try first. However, it doesn’t work under Snow Leopard—just Lion or later. DiskMaker X is the next-easiest method, but I’ve experienced the occasional failure with it. (DiskMaker X also doesn’t work under Snow Leopard.) The Disk Utility method is very reliable, and it works under Snow Leopard, Lion, Mountain Lion, and Mavericks.

Note: There’s one significant difference between the three methods that you should be aware of. Based on my testing, if the drive onto which you’re installing Mavericks doesn’t already have a Recovery HD partition, a bootable installer drive made using createinstallmedia or DiskMaker X (which uses createinstallmedia under the hood) can create that partition during the 10.9-install process. A bootable Mavericks installer drive made using the Disk Utility procedure will not. You can determine whether or not your Mac has a Recovery HD partition using the instructions in our article on recovery mode.

Whichever method you use, you need a Mac-formatted drive (a hard drive, solid-state drive [SSD], thumb drive, or USB stick) that’s big enough to hold the installer and all its data—I recommend at least an 8GB flash drive, though anything larger than roughly 5.5GB should work. That drive must also be formatted with a GUID Partition Table. Follow this tutorial to properly format the drive.

Option 1: Use createinstallmedia

Hidden inside the Mavericks installer is a Unix program called createinstallmedia, provided by Apple for creating a bootable Mavericks installer. If you’re comfortable using Terminal, it’s a relatively simple tool to use. The program assumes your account has administrator privileges.

Note: This method does not work in Snow Leopard. It works only in Lion, Mountain Lion, or Mavericks. (The resulting installer drive will let you install Mavericks over Snow Leopard, but you can’t create the installer drive while booted into Snow Leopard.) If you need to create a Mavericks install drive while booted into Snow Leopard, you should use the Disk Utility instructions, below.

1. Download the Mavericks installer from the Mac App Store and make sure it’s in your main Applications folder. (This means that if you followed my advice to move the installer out of your Applications folder, you’ll have to move it back, at least temporarily. The Terminal command I’m using here assumes the installer is in its default location.)
2. Connect to your Mac a properly formatted 8GB (or larger) drive. Rename the drive to Untitled. (The Terminal command used here assumes the drive is named Untitled.)
3. Select the text of this Terminal command and copy it: sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction
4. Launch Terminal (in /Applications/Utilities).
5. Paste the copied command into Terminal and press Return. Warning: This step will erase the destination drive or partition, so make sure it doesn’t contain any valuable data.
6. Enter your admin-level account password when prompted.
7. The Terminal window displays the progress of the process, in a very Terminal sort of way, by displaying a textual representation of a progress bar: Erasing Disk: 0%… 10%…20%… and so on. The program then tells you it’s copying the installer files, making the disk bootable, and copying boot files. Wait until you see the text Copy Complete. Done. (see the screenshot below), which could take as long as 20 or 30 minutes, depending on how fast your Mac can copy data to your destination drive.

You now have a bootable Mavericks-install drive. If you’re curious about createinstallmedia, type or paste the following command in Terminal and press Return:

sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia

The resulting text output shows you the (brief) instructions for using createinstallmedia more generically. (Thanks to a developer on Apple’s Developer Forums for pointing out createinstallmedia a few months ago.)

Option 2: Use Disk Utility

You’ll find Disk Utility, a handy app built into OS X, in /Applications/Utilities. Here are the steps for using it to create your installer drive, which are a bit more involved with Mavericks than they were with Mountain Lion and Lion.

Note: As mentioned above, based on my testing, an installer drive created using Disk Utility will not create a Recovery HD partition if your Mac’s drive doesn’t already have one. You can determine whether or not your Mac has a Recovery HD partition using the instructions in our article on recovery mode. If your Mac’s drive is missing the Recovery HD partition, you should use the createinstallmedia instructions, above, as the resulting installer drive will create the missing partition when you install Mavericks.

1. Once you’ve downloaded Mavericks, find the installer on your Mac. It’s called Install OS X Mavericks.app and it should have been downloaded to your main Applications folder (/Applications).
2. Right-click (or Control+click) the installer, and choose Show Package Contents from the resulting contextual menu.
3. In the folder that appears, open Contents, then open Shared Support; you’ll see a disk image file called InstallESD.dmg.
4. Double-click InstallESD.dmg in the Finder to mount its volume. That volume will appear in the Finder as OS X Install ESD.
5. The file you want to get to is actually another disk image inside OS X Install ESD called BaseSystem.dmg. Unfortunately, BaseSystem.dmg is invisible, and because this is a read-only volume, you can’t make BaseSystem.dmg visible. Instead, you’ll mount it using Terminal, which makes it visible in Disk Utility. Open the Terminal app (in /Application/Utilities), and then type open /Volumes/OS X Install ESD/BaseSystem.dmg and press Return.
6. Launch Disk Utility (in /Applications/Utilities). You’ll see both InstallESD.dmg (with its mounted volume, OS X Install ESD, below it) and BaseSystem.dmg (with its mounted volume, OS X Base System, below it) in the volumes list on the left.
7. Select BaseSystem.dmg (not OS X Base System) in Disk Utility’s sidebar, and then click the Restore button in the main part of the window.
8. Drag the BaseSystem.dmg icon into the Source field on the right (if it isn’t already there).
9. Connect to your Mac the properly formatted hard drive or flash drive you want to use for your bootable Mavericks installer.
10. In Disk Utility, find this destination drive in the left sidebar. You may see a couple partitions under the drive: one named EFI and another with the name you see for the drive in the Finder. Drag the latter—the one with the drive name—into the Destination field on the right. (If the destination drive has additional partitions, just drag the partition you want to use as your bootable installer volume.)
11. Warning: This step will erase the destination drive or partition, so make sure it doesn’t contain any valuable data. Click Restore, and then click Erase in the dialog box that appears; if prompted, enter an admin-level username and password.
12. Wait for the restore procedure to finish, which should take just a few minutes.
13. In Disk Utility, select BaseSystem.dmg on the left (not OS X Base System) and click the Eject button in the toolbar. This action unmounts the disk image named OS X Base System. (If you don’t do this, you have two mounted volumes named OS X Base System—the mounted disk image and your destination drive—which makes the next step more confusing.)
14. Open the destination drive—the one you’re using for your bootable install drive, which has been renamed OS X Base System. Inside that drive, open the System folder, and then open the Installation folder. You’ll see an alias called Packages. Delete that alias.
15. Open the mounted OS X Install ESD volume, and you’ll see only a folder called Packages. Drag that folder into the Installation folder on your destination drive. (You’re basically replacing the deleted Packages alias with this Packages folder.) The folder is about 4.8GB in size, so the copy will take a bit of time, especially if you’re copying to a slow thumb drive.
16. Eject the OS X Install ESD volume.
17. If you like, you can rename your bootable installer drive from OS X Base System to something more descriptive, such as OS X Mavericks Installer.

(Note that there is a way to perform this procedure that doesn’t require Terminal. However, it adds other steps, and it requires making all invisible files visible in the Finder. Because seeing all the Finder’s normally invisible detritus can be a bit disconcerting, I’ve opted for using Terminal in Step 5.)

Option 3: Use DiskMaker X

DiskMaker X (previously called Lion DiskMaker) is a utility that makes it easy to create a bootable OS X install drive, and version 3 supports the Mavericks installer. In fact, under the hood, DiskMaker X 3 actually uses the new createinstallmedia program.

Notes: Because DiskMaker X 3 uses createinstallmedia, it does not work under Snow Leopard. (The resulting installer drive will let you install Mavericks over Snow Leopard, but you can’t create the installer drive while booted into Snow Leopard.) In addition, DiskMaker X 3 hasn’t worked perfectly for me. For example, I experienced an issue where the utility alerted me that it couldn’t properly name the drive it was creating; however, the installer drive appeared to function properly. If DiskMaker X doesn’t work for you, you can use one of the other two methods, above.

1. Connect to your Mac a properly formatted 8GB (or larger) drive.
2. Make sure the Mavericks installer, called Install OS X Mavericks.app, is in your main Applications folder (/Applications). If you followed my advice to move the installer out of your Applications folder, you’ll have to move it back, at least temporarily.
3. Launch DiskMaker X.
4. Click OK on the warning screen that appears.
5. In the Welcome screen, click Mavericks (10.9).
6. You’ll see a dialog box alerting you that DiskMaker X found a copy of the installer in /Applications, and asking if you wish to use this copy. If you have multiple OS X installers (say, Mavericks and Mountain Lion), make sure the DiskMaker X message indicates that it has found the Mavericks installer. If so, click Use This Copy. If not, click Use Another Copy and manually locate the Install OS X Mavericks app.
7. The next dialog box asks which kind of disk you’ll be using as your bootable install drive. If you have an 8GB thumb drive, click that button; otherwise, click Another Kind Of Disk.
8. The next dialog box presents a list of available drives. Select the one you want to use and click Choose This Disk.
9. You see a warning that proceeding will erase both the selected volume and any other partition on the same disk. In other words, the drive you’ve chosen will be erased, so make sure it doesn’t contain any valuable data. Click Erase Then Create The Disk.
10. The next dialog box lets you know that you’ll be asked to provide an administrator username and password to build the install drive. Click Continue; when prompted a few seconds later, enter that username and password.
11. As I mentioned in my review of an earlier version of DiskMaker X (then called Lion DiskMaker), there will be times in the process when it appears as if nothing’s happening, so be patient. Once the process is complete, DiskMaker X will display a confirmation dialog box. Unlike with the Disk Utility approach, DiskMaker X helpfully names the bootable installer volume Install OS X Mavericks.

Booting from the installer drive

Whichever of the three processes you’ve used, you can now boot any Mavericks-compatible Mac from the resulting drive: Just connect the drive to your Mac and either (if your Mac is already booted into OS X) choose the install drive in the Startup Disk pane of System Preferences or (if your Mac is currently shut down) hold down the Option key at startup and choose the install drive when OS X’s Startup Manager appears.

When your Mac is booted from your installer drive, you can, of course, install the OS, but you can also use any of the Mavericks installer’s special recovery and restore features. Depending on how you made your installer drive, when you boot from that drive, you may even see the same OS X Utilities screen you get when you boot into OS X Recovery (recovery mode). However, unlike with recovery mode, your bootable installer includes the entire installer.