Here is how to make a bootable usb of the yosemite public beta installers. It is much easier than for yosemite DP1 and similar to how you do it for mavericks (but obviously the installer name has changed). Format an 8 GB USB drive which should be called Untitled and formatted as Mac OS Extended (Journaled). The installer should be called Install OS X Yosemite Beta.app and should be in your Applications folder. Run this in terminal and wait about 20 minutes: sudo /Applications/Install\ OS\ X\ Yosemite\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Yosemite\ Beta.app --nointeraction You can boot up from it by selecting it from the startup manager you get when starting your computer and holding down the option key. EDIT: This code was first used for PB1 but also works for PB2, PB3 and PB4.