Apple - What is the best way to generate a Yosemite or Mavericks Install USB flash drive?

Edit: this also should work for El Capitan with a 6.33GB+ partition

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Currently the best way seems to be through createinstallmedia, which is also Apple's recommended method.

First create a Mac OS Extended (Journaled) partition on the USB key with 5GB or more:

then in the terminal use the createinstallmedia command. It can be found in the Maverick install apk. By default the path is /Applications/Install OS X Mavericks.app/Contents/Resources/createinstallmedia.

Replace /Volumes/MavericksInstall with your own partition name:

sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MavericksInstall --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction

The output should be along these lines:

Copying installer files to disk...
Copy complete.
Making disk bootable...
Copying boot files...
Copy complete.
Done.

The setup should take few to few dozens minutes depending on your USB drive.

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To create a USB installer for multiple OS X versions you can to go through the following procedure:

• Start disk utility
• Create multiple partitions formatted as Mac OS Extended (Journaled). Give them names like:
  • OS X Lion : LionInstall
  • OS X Mountain Lion : MountainLionInstall
  • OS X Mavericks : MavericksInstall

• Generate multiple install partitions using the createinstallmedia tool of each OX 10.9+ version and add the other install partitions using disktool :
  • restore the InstallESD.dmg from /Applications/Install Mac OS X Lion/Contents/SharedSupport to /Volumes/LionInstall
  • restore the InstallESD.dmg from /Applications/Install OS X Mountain Lion/Contents/SharedSupport to /Volumes/MountainLionInstall
  • sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MavericksInstall --applicationpath /Applications/Install\ OS\ X\ Mavericks.app --nointeraction

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From experience here is the data usage for each OS X version :

• OSX 10.6 Snow Leopard: 7.19GB
• OSX 10.7 Lion: 4.78GB (requires 6.13 GB)
• OSX 10.8 Mountain Lion: 4.48GB
• OSX 10.9 Mavericks: 5.4GB
• OSX 10.10 Yosemite: 5.25GB
• OSX 10.11 El Capitan: 6.33GB
• macOS Sierra: 4.84GB

The absolute easiest way (Trust me on this) is to download this application LionDiskMaker and it will do everything everyone have said, only it will do it all automatically

(feel free to donate (I'm not the creator of the app, however it works perfectly))

Direct Download link!

Assuming that you have a USB flash drive plugged into the computer that has the name "Untitled", my preferred method to create a bootable Mavericks install disk would probably be:

hdiutil mount "/Applications/Install OS X Mavericks.app/Contents/SharedSupport/InstallESD.dmg"

sudo asr restore --source "/Volumes/OS X Install ESD/BaseSystem.dmg" --target /Volumes/Untitled --erase

sudo unlink "/Volumes/OS X Base System/System/Installation/Packages"

sudo cp -Rp "/Volumes/OS X Install ESD/Packages" "/Volumes/OS X Base System/System/Installation"