How to Create a Bootable Install Drive for Macs Preinstalled with Mavericks

In our previous article that How to Create a Bootable Mavericks Install Drive, we have listed many good reasons to create a bootable Mavericks install drive. In a word, a bootable installer drive makes it faster and easier to install Mavericks on multiple Macs. In the article How to Create a Bootable Mavericks Install Drive, we give instructions creating a bootable Mavericks installer drive for those who purchased Mavericks from the Mac App Store. And this article is especially for those who own a newer Mac that is shipped with OS X 10.9.

If you got a newer Mac shipped with Mavericks, to create a bootable Mavericks install drive is not so easy because you don't have an easily downloadable version of the installer. Anyway, there is still a way to make it. You have to prepare yourself well for this because the way we are going to introduce to you needs more work than if you have purchased the Mac App Store version. Here we go.

Firstly, we need to play a little trick to grab the installer data from OS X Recovery.

Note: OS X Recovery is a new feature of recent OS X version. It enables you to boot your Mac into a special recovery mode to repair your hard drive, restore your drive from a backup, or reinstall OS X itself. You might say why we need a bootable external hard drive then if the OS X Recovery can do the same job. Theoretically, it is true that we don't need to make a bootable install drive if there is OS X Recovery. But, in fact, a bootable installer drive is better than OS X Recovery. For example, a bootable installer makes the installation much faster than OS X Recovery. OS X Recovery requires you to download over 5GB of data before you can reinstall Mavericks while a bootable installer drive doesn't because it already contains all necessary data but OS X Recovery not. Anyway, to have a bootable install drive only does good for you.

OK, let's continue. How to grab the installer data then? Here we go:

When using OS X Recovery to reinstall Mavericks, you Mac will contact Apple's servers, get identified to request Mavericks installer data. When Apple's servers verify your Mac, it will offer installer data for download. When finishing download the data, OS X Recovery will restart your Mac and then install the OS. And the installer data will be deleted very soon. So, what we need to do is to grab the installer data safely during that process. Follow these steps:

Step1. Boot into OS X Recovery. Hold down Command+R at startup to boot into recovery mode and you'll view the OS X Utilities window (see screenshot below). And then connect a drive with at least 12 GB of free space.

Step2. Choose "Reinstall OS X" from the OS X Utilities window and then press "Continue" button, and then there is the OS X Mavericks screen with "Continue" button. Click on it. And the message saying "To download and restore OS X, your computer's eligibility will be verified with Apple" pops up. Follow the instructions on the next screen to agree the license agreement.

Step3. Choose the drive on which you attempt to install Mavericks. Make sure to choose the external drive instead of the Mac's drive. And then click "Install" to start downloading. It can take a long while to complete the download. Good luck.

Step4. Keep an eye on the progress bar. When it gets near the end, get ready to interrupt it. Once the status says about 0 seconds left, the progress bar will disappear with the screen turning gray. Quickly, the installer will take a minute or two to clean up and as said above, restart your Mac. Once your Mac restarts, it will unplug your external drive and boot into the OS X installer on the external drive and start the installation process. So, you need to interrupt that process to keep your Mac from installing OS X.

Step5. When your Mac booted from its normal startup volume, you need to reconnect the external drive. And then open it to find the OS X Install Data folder. Open the folder to see if there is a file named InstallESD.dmg.

Note: If you want to use the same hard drive for your bootable installer drive, please copy the InstallESD.dmg disk image to your Mac's internal drive. You gonna need it in the following steps.

After we get the installer data, let's move on to create a bootable installer drive.

Step1. Double click the InstallESD.dmg disk image in the OS X Install Data on your external drive to mount its volume which will turn up in the Finder as OS X Install ESD.

Step2. We'll need the disk image called BaseSystem.dmg inside OS X Install ESD. However, this disk image is read-only and invisible; we have to use Terminal to make it visible in Disk Utility. To do that, open the Terminal app in /Application/Utilities or you can type and search it on Spotlight Search. When open the Terminal, type open /Volumes/OS\ X\ Install\ ESD/BaseSystem.dmg and then press Return.

Step3. Open Disk Utility and then you should see InstallESD.dmg and BaseSystem.dmg in the volumes list on the left. Choose BaseSystem.dmg in Disk Utility's sidebar and then press the "Restore" button. If the BaseSystem.dmg icon is not in the Source field please drag it into there on the right.

Step4. Connect the formatted hard drive which you want to use for the bootable Mavericks installer to your Mac. And then find it in Disk Utility. In Disk Utility, you might see two partitions below the destination drive. Please drag the one with the name for the drive into the Destination field on the right. If there are more partitions under the destination drive, you can just drag the one you want to use as the bootable installer volume.

Step5. Press the "Restore" button and then click "Erase" in the followed up dialog. You'll be asked to enter admin username and password to allow this action. Please note that this action will erase the destination drive or partition. So, please ensure it doesn't include any valuable data. After you allow this restore thing to continue, it starts restore procedure. This might take a few minutes.

Step6. Unmount the disk image called OS X Base System by choosing BaseSystem.dmg in Disk Utility on the left and then clicking "Eject" button in the toolbar.

Step7. Launch the destination drive for bootable install drive. In that drive, open the System folder-Installation folder. Find the alias called Packages and drag it to Trash.

Step8. Go to open the mounted OS X Install ESD volume. Find the folder called Packages and drag it to the Installation folder on your destination drive. When finishing copying the Packages onto your destination drive, eject the OS X Install ESD volume.

Step9. Rename the bootable installer drive if you like.

Done! You are now able to use this drive to boot almost any Mavericks compatible model and install Mavericks. This instruction might be a little bit complicated to those not so good at computer. Anyway, just be patient to clarify the steps before you start the procedure.