I’m using a workflow from Apple’s KB article HT201372. It works really well and doesn’t require any 3rd party scripts. You will need to download the installer for either Yosemite or Mavericks from the AppStore. If you have already installed yours you can download another copy by looking in your Purchases. If it is currently on your HD, you can dump it and install the latest by going to Macintosh HD and looking in the /Applications folder. This is different than your user ~/Applications folder.
Once you have downloaded the installer app you will see the button change to “Downloaded” under your Purchases.
You will need a USB drive with at least 8Gb or more.
Run the following command in Terminal. sudo /Applications/Install OS X Yosemite.app/Contents/Resources/createinstallmedia –volume /Volumes/MyVolume –applicationpath /Applications/Install OS X Yosemite.app
Where it says, “/Volumes/MyVolume” you will want to replace with the path to your USB drive. For example, mine was /Volumes/Yosemite – then hit return. You should see the following on the Terminal screen.
When you have finished, it will remount your USB drive as Install OS X Yosemite. If you open the directory, you should see the following:
That’s it. Very simple, or at least compared to other utilities I’ve used to do the same thing.
For more info check out: https://support.apple.com/en-us/HT201372
