When Apple released Mac OS X 10.9 Mavericks (still hate that name, but I never cared for the cats either), they changed the workaround we were using to manually build bootable thumb drives. But as it turns out, there is now a lengthy Terminal command will literally build a bootable USB drive for you.
In its simplest form, just copy and paste this command into your Mac’s Terminal window and hit return. You will be prompted to enter your administrator password in order to write to the USB drive. Please keep in mind that this command will erase the USB drive that is attached to your computer if it is named USB8GB. If you’re using a USB drive with a different name, you will need to either rename the drive or modify this command.
sudo /Applications/Install\ OS\ X\ Mavericks.app/Contents/Resources/createinstallmedia –volume /Volumes/USB8GB –applicationpath /Applications/Install\ OS\ X\ Mavericks.app –nointeraction
Once the command is executed, the contents of the USB drive named USB8GB will be destroyed without requiring any confirmation. The process will take some time but the system will initialize the drive and then copy the necessary files to the device. Once the Terminal shows that the command has finished executing, you will have a bootable USB drive than can be used to perform a clean install of OS X 10.9, run the Disk Utility, or boot the system into the command line.