With OS X Mavericks and Yosemite, you can create a bootable OS X installer that can be used to install the operating system when booting from removable media, such as a USB flash drive.
Before you can create a bootable OS X installer, you need to do the following:
- Download the OS X installer App from the Mac App Store.
- Mount the volume that you want to convert to a bootable installer. This volume can be removable media (such as a USB flash drive) or an internal alternate partition.
- You can then use the Createinstallmedia tool to convert the volumes in the second step to a bootable installer based on the installer app in the first step. To learn how to use Createinstallmedia, execute the following command in Terminal:
OS X Yosemite
/Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia
OS X Mavericks
/Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia
Example
For example, suppose you mount a volume to "/volumes/myvolume" and the OS X installer app is in "/Application/install\ os\ x\ Mavericks.app", you can erase "/volumes/myvolume", and convert it to a bootable installer using the following command:
OS X Yosemite
sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Yosemite.app
OS X Mavericks
sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume --applicationpath /Applications/Install\ OS\ X\ Mavericks.app
Note
- You may need to adjust the path of the OS X Installer app and/or the name of the removable media device in the command.
- Createinstallmedia is an advanced option for system administrators and therefore requires some command-line knowledge to be used correctly. It can only be used with the version of OS X installer app that accompanies it.
Making Mac system installation USB drive