Creating a Bootable USB for Macs

Apple has created a support page http://support.apple.com/kb/ht5856 which directs you to https://support.apple.com/en-ca/HT201372 that explains, in large, how to create a bootable USB drive with the OS X 10.9 Mavericks setup file on board. It is not very detailed (which is where the following steps come in), but is to be preferred over dedicated, third-party tools as it is properly tested.

That being said, this option is only aimed at those whose Macs are already running the latest iteration of the Mac operating system, according to the support page.

Here is what you need to do:

• Use the Mac App Store to download the OS X installer app but do not install (you are only interested in the Install\ OS\ X\ Yosemite.app).
• Connect the USB drive to your Mac. Backup any files that may be stored on it.
• Format it, using Disk Utility, as a Mac OS Extended (Journaled) drive, named Yosemite. This can be done from the Erase tab within the app; make sure the USB drive does not have multiple partitions (that can happen, so turn to the Partition tab to verify and correct this).
• Open Terminal.
• Type (paste) the following command: sudo /Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Yosemite --applicationpath /Applications/Install\ OS\ X\ Yosemite.app --nointeraction
• To kick off the process, type in your user password when requested.

As there is no progress bar or percentage indicator, there is no way of knowing how much time the process will take to complete. It mostly depends on the speed of your USB drive. It should take 30 minutes at most (it is not a rule, just a personal observation based on my experience).

Note: Possible Problems

/Applications/Install\ OS\ X\ Yosemite.app/Contents/Resources/createinstallmedia --volume /Volumes/Yosemite/ --applicationpath /Applications/Install\ OS\ X\ Yosemite.app/ --nointeraction Erasing Disk: 0%... 10%... 20%... 30%...100%...

Copying installer files to disk...

Copy complete.

Making disk bootable...

Couldn't mount dmg /Volumes/OS X Install ESD/BaseSystem.dmg (error code 112)Copying boot files...

Failed to copy kernelcache, The file “kernelcache” couldn’t be opened because there is no such file.

The kernelcache problem. I downloaded an app called "!Diskmaker X" and am using this to create a bootable USB drive now. Something possibly is wrong with the Apple createinstall app.

-- EdwardChrzanowski - 2014-10-07