In most cases, upgrading to OS X Mavericks from an older version of OS X is simple. Just launch the Apple App Store, download the upgrade, and install it. In some cases, however, it may be necessary to install a fresh copy of Mavericks by booting from an external thumb drive. The following instructions will walk you through step-by-step on how to make your very own Mavericks bootable thumb drive.
If you follow the steps exactly as outlined, total time to completion is 20-30 minutes. This includes everything you need to create a clean, bootable thumb drive AND proper clean-up afterwards.
What you need
- USB Thumb Drive (8 GB or larger)
- OS X 10.9 Mavericks installer file
Step 1) Download OS X 10.9 Mavericks
- Open the App Store and begin downloading OS X 10.9 Mavericks (direct link)
- When the download has completed, DO NOT INSTALL
- Open Finder then click on "Applications"
- Right-click on the "Install Mac OS X Mavericks" app and choose "Show Package Contents"
- Browse to Contents/SharedSupport
- Right-click on the file called "InstallESD.dmg" and choose "Copy"
- Right-click on your Desktop and choose "Paste" to put a copy of the file on your Desktop
Step 2) Prepare the thumb drive
- Insert your thumb drive
- Open Disk Utility (Applications > Utilities)
- Highlight the thumb drive on the left side of Disk Utility
- Click the "Partitions" tab
- Warning: the following steps will erase all contents on your thumb drive
- From the "Partitions Layout" drop-down menu, select "1 Partition"
- From the "Format" drop-down menu, select "Mac OS Extended (Journaled)"
- Click on "Options..."
- Choose the "GUID Partition Table" option, then click "OK"
- Click "Apply"
- Confirm the change to continue by clicking "Partition"
- Quit Disk Utility
Step 3) Enable "Show Hidden Files"
- Open "Terminal" (Applications > Utilities)
- Type "defaults write com.apple.finder AppleShowAllFiles TRUE" <enter>
- Quit "Terminal"
Step 4) Mount the installer
- Double-click on the "InstallESD.dmg" file (on your Desktop)
- Notice the file called "BaseSystem.dmg" (grayed out)
- Move the resulting Finder window to one side of your screen
- Open Disk Utility and drag it to the opposite side of your screen so you can see both windows
- Highlight your thumb drive on the left side of Disk Utility
- Click not he "Restore" tab
- Drag the "BaseSystem.dmg" file from the "InstallESD.dmg" Finder window to the "Source" field in Disk Utility
- Drag the thumb drive partition "Untitled 1" on the left side of Disk Utility to the "Destination" field in Disk Utility
- Click "Restore" then "Erase" (this process will take 5-10 minutes)
- Quit Disk Utility and close all Finder windows
Step 5) Copy the Installer Packages
- Double-click on the "InstallESD.dmg" file (on your Desktop)
- Right-click on the folder called "Packages" and choose "Copy"
- On the left side of the Finder window, select your thumb drive now called "OS X Base System"
- Browse to System/Installation
- Delete the alias called "Packages"
- Right click in the white space in the same directory and choose "Paste" (this will paste the "Packages" folder from "InstallESD.dmg" to the thumb drive
- After the copy finishes (this will take 15-20 minutes), close all Finder windows
Step 6) Disable "Show Hidden Files" in Finder
- Open "Terminal" (Applications > Utilities)
- Type "defaults write com.apple.finder AppleShowAllFiles FALSE" <enter>
- Quit "Terminal"
When all steps are completed, you are welcome to either continue with the upgrade to OS X Mavericks on your Mac if you haven't already, or cancel the install and delete the "Install OS X Mavericks" app in Applications. You now have a bootable thumb drive with OS X Mavericks.
