Source: http://www.macworld.com/article/2367748/how-to-make-a-bootable-os-x-10-10-yosemite-install-drive.html Back in the day when we bought OS X on discs, as long as you kept that disc, you always had a bootable installer just in case. Modern, downloadable versions of OS X create a recovery partition on your drive, but it’s always a smart idea to make your own bootable installer drive too. I recommend…