Create Yosemite USB-drive Installer03 Jun 2014
Update October 19, 2014
With the release version of OS X 10.10,
createinstallmedia finally works. You can follow the same procedure as when creating the USB installer for OS X 10.9 – just update the Terminal command to reflect the downloaded Yosemite Installer. If you prefer the GUI approach, have a look at DiskMaker X. I won’t cover DiskMaker X here.
The short version
- USB-media. A USB-stick, 8GB or more. Format the media as Mac OS X Extended (Journaled) with GUID partition mapping. Name it
- Download the Yosemite Installer for the App Store. It launches after the download is finished, but just quit the installer.
- Use Terminal (/Applications/Utilities/Terminal) to create the USB-installer
In Terminal, enter:
$ sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
Type in your administrative password.
Wait 15-20 minutes for the process to finish. You can now boot from the newly created USB installer holding down the option-key during startup.
Tip for Homebrew users (and others with a lot of content in /usr/local)
If you have lots of non-Apple files in
/usr, the Yosemite upgrade might take may hours. Use this tip from Jim Lindley on moving the content in
/usr/local before upgrading.
End update 2014-10-19
In OS X 10.9 Mavericks, Apple introduced a new way of creating a USB installer with the
The executable is present also in OS X 10.10 Yosemite Developer Preview, but there seems to be a bug which prevents the process to carry through.
In the meantime you can create a Yosemite boot stick much in the same way as early Maverics builds worked.
Mount the InstallESD.dmg image that’s under the installer /Contents/SharedSupport.
Mount BaseSystem.dmg using the Terminal
$ open "/Volumes/OS X Install ESD/BaseSystem.dmg"
Using Disk Utility, Restore the “OS X Base System” volume to your USB stick.
Not necessary, but to make things easier, rename the USB stick something else. I use “yosemiteDP1”
On the USB stick, in the folder System/Installation, delete the symlink named “Packages”
Copy the “Packages” folder from “OS X Install ESD” to the System/Installation folder on your USB stick.
Using Terminal, copy BaseSystem.dmg and BaseSystem.chunklist (they are both hidden from the Finder) from OS X Install ESD to your USB stick
$ cp "/Volumes/OS X Install ESD/BaseSystem.* /Volumes/yosemiteDP1"
Unmount the stick, boot away.
Let’s hope this bug is fixed before Yosemite DP2
Update I 2014-07-08: Still broken in DP3
Update II 2014-07-08: The new installer downloaded from App Store is still DP1, so I can’t verify the statement in Update I.