So, I seem to be effecting something with that command, but I still can't boot from my Windows bootable USB drive. The log in screen, though, was much slower than usual, as if something else was happening in the background. Boot was slower, but then I was presented with the normal log-in screen. Sudo bless -mount '/Volumes/WDO_Media32/' -legacy -setBoot -nextonlyĪnd then did a restart. Or maybe a better question, if there isn't a simple answer, would be what does Bootcamp do to allow booting from a Windows install DVD or to allow Windows, once installed, to boot?ĮDIT: I was able to sort of get results using the bless command in Terminal. So, what do I have to do to get my Mac to recognize and boot from another OS on a USB flash drive? I have had the same issue trying to use the Ultimate Boot CD on a USB, various Live USBs for Linux, etc. Specifically, I was running Windows 7 on my Mac to create the bootable disk, which has Windows Defender Offline on it. I know the drive works and is bootable, because it works with my friend's Windows PC. I'm trying to get my Mac to boot from a USB flash drive.