

With the USB drive selected, choose the Partition tab on the right side of the window.

Note that you want to select the drive and not the volume. We’re using a SanDisk Cruzer flash drive, so in our case we choose 8 GB SanDisk Cruzer Media and not the default “No Name” volume. In Disk Utility, select the USB flash drive from the list on the left. Plug the drive into a Mac running OS X 10.7 Lion or higher and launch Disk Utility from the /Applications/Utilities folder. While it’s possible to create a separate partition for the Yosemite USB installer, it’s safest and easiest to use an empty drive or one that you don’t mind erasing. Grab a USB flash drive that’s at least 8GB in size. It will also launch the Yosemite installer app when the download completes. This will put a file called Install OS X Yosemite Beta.app in your /Applications folder. If you’re registered for the Yosemite beta program, download the OS X Yosemite Public Beta installer from the Mac App Store. Step 1: Obtain the Yosemite Public Beta Installer
