Plug the external usb drive into mac make sure you save your stuff from it. Open terminal which is in the utilities folder of your applications folder. If you have already installed this version of macos you. Once you attached the usb drive it will shown on the left panel of disk utility. Look for the version of macos you want in the store if you have previously downloaded the version search under your purchased tab. This method also works to creating usb installer for el capitan yosemite and maverick and the other previous version of mac os x as well. Use the restore disk image to drive dialog box to browse for the dmg file with the installation files for mac os x yosemite in this case and click the ok button to create a bootable usb of the operating system. How to get older macos installation files. Now click on erase.ĭownload And Create Usb Installer For Mac Os X Yosemite Mavericks Mountain Lion Or Lion Macbold You will create the bootable installer from this app not from the disk image or pkg installer.Ĭreate bootable usb mac disk utility yosemite. 8gb or greater usb install os x yosemite zip file downloaded from mac store download from here now let s move to the actual tutorial to create bootable os x yosemite usb connect your usb drive with mac.