- Choose external drive in Disk Utility
- Go to “Partition” tab, select “1 Partition” from select, then click “Options” and choose “GUID Partition Table” then “OK”
- Choose “Apply”
- Open terminal
- Execute this command with your paths informations
$ sudo /path_to_mavericks_app/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia --volume /Volumes/my_external_drive --applicationpath /path_to_mavericks_app/Install\ OS\ X\ Mavericks.app --nointeraction