1. there might be a problem with your USB, try another one. 2. redownload the ISO and try again. 3. you are doing it wrongly. InsanelyMac Bootable USB, Moutain Lion 10.8.2 - New Users Lounge
: Often, the installation wouldn't just start. You’d have to type cryptic "boot flags" like (verbose mode to see where it crashed) or GraphicsEnabler=No Niresh 12495 OSX 10.8 Mountain Lion USB Bootable For