Making Mac system installation USB drive

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:

1. Download the OS X installer App from the Mac App Store.
2. 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.
3. 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