Users that have upgraded to Yosemite may also get this same error. This should then allow you to continue on with the installation as normal and Fix Error Your bootable USB drive could not be created one and for all. However this time instead of selecting the DVD drive, go into your Documents folder and select the newly created DMG or ISO file. Once you have created your DMG or ISO file, you can then start the process again with the Boot Camp Assistant. If you want to know how to create a ISO or DMG file from a DVD then you can follow the video here. But also you will need to make a copy of that DVD so that you will be able to continue along with the setup. You need to unmount the USB drive in order to get this to work. The fix for this is pretty straight forward. The problem is the DVD is already mounted in Disk utility and when this is the case the Boot Camp Assistant cannot mount the DVD at the same time so you get this Error Your bootable USB drive could not be created. When installing Windows on a Mac I came across this error when I was trying to create a USB drive. This video and article will show you how to Fix Error Your bootable USB drive could not be created.