Apple – Create an OS X 10.9 Mavericks bootable USB flash drive or ISO

This week Apple released OS X 10.9 Mavericks for free through the App Store. Even though downloading from the App Store works great for updating, I also want to be able to perform a clean install and create VMs running OS X 10.9 Mavericks. I also don’t want to download the 5+GB update file every time I upgrade a system.

Unfortunately Apple doesn’t provide an ISO download or a tool to create an ISO or bootable USB drive. There are however many people with similar needs that provide information on how to create both. The downside of these methods though, is that you need to have a working OS X system to be able to use them.

Create an OS X 10.9 Mavericks bootable USB flash drive

1. From your current OS X installation, go to the App Store and download OS X Mavericks. Do not perform the installation until you’re done, because otherwise it will remove the 5+ GB file you need.
2. Format an 8GB or larger USB drive as “Mac OS Extended (Journaled)” and give it a name or keep the default of “Untitled“.
3. From Terminal , run the following command (replace Untitled with the name you used):
   sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction

Alternatively you can use the graphical user interface (GUI) tool Diskmaker X (formerly Lion DiskMaker).

Create an OS X 10.9 Mavericks bootable ISO

1. From your current OS X installation, go to the App Store and download OS X Mavericks. Do not perform the installation until you’re done, because otherwise it will remove the 5+GB file you need. Also make sure you have sufficient space to hold the temporary files and the resulting output file.
2. Run the commands in Terminal as decribed in “HOWTO: Create bootable Mavericks ISO“:

# Mount the installer image
hdiutil attach /Applications/Install\ OS\ X\ Mavericks.app/Contents/SharedSupport/InstallESD.dmg -noverify -nobrowse -mountpoint /Volumes/install_app

# Convert the boot image to a sparse bundle
hdiutil convert /Volumes/install_app/BaseSystem.dmg -format UDSP -o /tmp/Mavericks

# Increase the sparse bundle capacity to accommodate the packages
hdiutil resize -size 8g /tmp/Mavericks.sparseimage

# Mount the sparse bundle for package addition
hdiutil attach /tmp/Mavericks.sparseimage -noverify -nobrowse -mountpoint /Volumes/install_build

# Remove Package link and replace with actual files
rm /Volumes/install_build/System/Installation/Packages
cp -rp /Volumes/install_app/Packages /Volumes/install_build/System/Installation/

# Unmount the installer image
hdiutil detach /Volumes/install_app

# Unmount the sparse bundle
hdiutil detach /Volumes/install_build

# Resize the partition in the sparse bundle to remove any free space
hdiutil resize -size `hdiutil resize -limits /tmp/Mavericks.sparseimage | tail -n 1 | awk '{ print $1 }'`b /tmp/Mavericks.sparseimage

# Convert the sparse bundle to ISO/CD master
hdiutil convert /tmp/Mavericks.sparseimage -format UDTO -o /tmp/Mavericks

# Remove the sparse bundle
rm /tmp/Mavericks.sparseimage

# Rename the ISO and move it to the desktop
mv /tmp/Mavericks.cdr ~/Desktop/Mavericks.iso