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How To Create a Bootable OS X Yosemite USB Installation Disk

Ever wondered how to create a bootable USB for installing OSX 10.10.5 (Yosemite)? Well I did and here is how it is done and it is not all that hard.

First part is to go to the App STore and download OS X Yosemite. This will take awhile to complete as it is a 5.27 GB download. While that is downloading you can get your 8 GB or higher USB key inserted and ready.

Once the download has completed the installation screen will come up. Do not click on anything but you can minimize the screen and open a terminal. Go > Utilities > Terminal.

First we need to know what the volume name is for the USB key. You can easily get this from the terminal or take the name showing on the desktop when you inserted the key and OS X mounted it and add /Volumes to the name. If you want it from the termoinal just type mount and look for the information. In this example mine is called /Volumes/OSX

mount
/dev/disk1 on / (hfs, local, journaled)
devfs on /dev (devfs, local, nobrowse)
map -hosts on /net (autofs, nosuid, automounted, nobrowse)
map auto_home on /home (autofs, automounted, nobrowse)
localhost:/gAggsG9D5-bdrVS27jr4BB on /Volumes/MobileBackups (mtmfs, nosuid, read-only, nobrowse)
/dev/disk2s2 on /Volumes/OSX (hfs, local, nodev, nosuid, journaled, noowners)

Next change into the directory:

cd "/Applications/Install OS X Yosemite.app/Contents/Resources/"

At this point we are ready to run the createinstallmedia command. The syntax is createinstallmedia -volume <usb media> -applicationpath <location of the Install OS X Yosemite.app> -nointeraction. So our final resut is that below.

$ sudo ./createinstallmedia -volume /Volumes/OSX -applicationpath "/Applications/Install OS X Yosemite.app" -nointeraction

It will take some time for it to complete, but afterwards you will have a bootable install disk for Yosemite.

Finally you can exit the Yosemite installer and it will delete itself from your system.

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