- 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).
- Right-click (or Control+click) the installer, and choose Show Package Contents from the resulting contextual menu.
- In the folder that appears, open Contents, then open Shared Support; you’ll see a disk image file called InstallESD.dmg.
- Double-click InstallESD.dmg in the Finder to mount its volume. That volume will appear in the Finder as OS X Install ESD.
- 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.dmgand press Return.
- 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.
- 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.
- Drag the BaseSystem.dmg icon into the Source field on the right (if it isn’t already there).
- Connect to your Mac the properly formatted hard drive or flash drive you want to use for your bootable Mavericks installer.
- 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.)
- 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.
- Wait for the restore procedure to finish, which should take just a few minutes.
- 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.)
- 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.
- 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.
- Eject the OS X Install ESD volume.
- 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.
- Connect to your Mac a properly formatted 8GB (or larger) drive.
- 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.
- Launch DiskMaker X.
- Click OK on the warning screen that appears.
- In the Welcome screen, click Mavericks (10.9).
- 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.
- 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.
- The next dialog box presents a list of available drives. Select the one you want to use and click Choose This Disk.
- 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.
- 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.
- 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.
Learn much more about Mavericks from our Total Mavericks Superguide ebook.
Updated 10/22/2013, 6:30p.m., to add the method for using OS X’s createinstallmedia command to create a bootable installer drive. Updated 10:45p.m. to indicate how long the createinstallmedia command can take. Updated 10/23/2013, 4:30p.m., to add note about createinstallmedia and Snow Leopard. Updated 10/24/2013 to reflect name change of Lion DiskMaker to DiskMaker X. Updated 10/27/2013 to note which methods will properly create the Recovery HD partition when necessary; to add link to instructions for creating a Mavericks-install CD; and to include minor edits for clarity. Updated 5/7/2014 to reference our article on creating a bootable Mavericks install drive for newer Macs.