If you like to try Mac OS X 10.10 Yosemite as a separate installation, then you must have an installer disk which is bootable to install the OS. Currently Mac OS X 10.10 Yosemite is available through Apple App store only. It can be downloaded through App store then used to upgrade the existing Mac OS X Mavericks. Most of us definitely will not like to update the current installation since OS X 10.10 still a beta release. Follow this simple steps to create bootable Mac OS X 10.10 Yosemite USB installer disk which can boot Mac hardware and any Hackintosh.
There are few methods available to create a bootable USB disk from the Yosemite App installer which was downloaded through Apple app store, but here I mention the easiest and quickest way. Since the Apple app store needs to be used for downloading OS X 10.10 beta from official website, you must have a working Mac OS X 10.9 Mavericks Operating System, it can be on Apple hardware or any virtualization software with Windows.
Go to this official beta site and download the OS X 10.10. It’s around 5.7 GB size. Once you have downloaded successfully, by default it will go under /Applications as shown below.
Easy Steps to Create Bootable Mac OS X 10.10 Yosemite USB Disk
This method will use a built-in UNIX command in Mac OS X (from Lion, Mountain Lion and Mavericks OS only), createinstallmedia. It works fine with current public beta release of Mac OS X 10.10 and I’m sure with future beta and final releases too.
1) Make sure you have downloaded the Yosemite installer by app store and its located under Applications ( as shown in above screenshot)
2) You must have a 8GB (or more) USB disk. It should be formatted and named as ‘Untitled’. As this method uses a terminal command to create a bootable disk, the below command assumes that your USB disk is named as ‘Untitled’.
3) Type below command in terminal. ‘Terminal’ is located under /Application/Utilities. Need to provide root-level password to proceed the command. Below command will erase the data in USB disk.
sudo /Applications/Install\ OS\ X\ Yosemite\ Beta.app/Contents/Resources/createinstallmedia –volume /Volumes/Untitled –applicationpath /Applications/Install\ OS\ X\ Yosemite\ Beta.app –nointeraction
If the downloaded content, the location of Yosemite installer App and name of USB drive are correct, the above command will work fine and you can see the successful message.
Safely unplug the USB disk. Now you have a bootable Mac OS X 10.10 Yosemite USB disk with you.
If you are interested in knowing some more methods to create bootable Yosemite USB disk, follow other steps here.