Trouble with createinstallmedia when making bootable USB to install Mavericks
I am have been trying to make a bootable USB to install Mavericks on a external partition (so I can continue to use iDVD 😝)
I have downloaded Maverick install app from App Store and I followed Apple's instructions from here Create a bootable installer for OS X - Apple Support
The Install OS x Mavericks drive appears when I hold down Option when booting, but then just hangs at a screen a circle with a line through its center (the international symbol for "No!")
I am using OS X El Capitan on a Mac Mini (late 2012)
Could anyone advise on what I am doing wrong?