Legacy USB Support Disabled
Save and exit the BIOS after making the changes. Western Digital's solution was to disable legacy USB option in BIOS Set up but that option could not be found, so they said I needed a BIOS upgrade.
With newer Windows 8 PCs that are designed with UEFI support, the BIOS or firmware often has an option that specifies if the computer can boot into regular operating systems and recovery tools, or if it can boot exclusively into newer UEFI operating systems and environments. - When Legacy USB Support is set to Disabled , I cannot use my USB keyboard to access the UEFI (or any other option during startup such as boot menu). I checked the BIOS and Legacy USB is enabled, and I know disabling it will disable all my USB ports, and I don't have a PS/2 keyboard. - Currently, I have Legacy USB Support set to UEFI Setup Only which allows the PC to boot into Windows 7 and allows me to use my USB devices within the UEFI. Once in the BIOS setup, check the menus for an option to enable or disable the onboard USB ports. Anyway, I have a Windows 7 installer (64 bit) on a USB, I changed my boot settings to boot from USB first, and I'm getting just a black screen with the sentence "Legacy Support Disabled in the Setup". Disable the USB ports through BIOS setup. You might see separate commands for the same device.
Some devices only support one mode (either UEFI or BIOS).
The PC is looking to the External HD as the boot drive. For example, select UEFI: USB Drive or BIOS: Network/LAN.
Make sure all USB options and Legacy USB support options are disabled or off. If your PC or laptop supports UEFI and legacy mode then the following tips may help you. If I set "Legacy USB Support" to "Disabled" from BIOS, I can no longer see the USB in the boot devices I can't see my HDD in the boot devices (although I can see it in windows installation process and with diskpart + list disk ) and thus can't set it to priority #1 as some have suggested on the internet Legacy Boot Mode. Enter the BIOS setup. Legacy enabled: If the bios setting is legacy enabled then hard drives and USB devices will normally boot. How to enter the BIOS or CMOS setup. Each command uses the same device and media, but boots the PC in a different firmware mode. For example, you might see UEFI USB Drive and BIOS USB Drive. Called HP - as the external hard drive was not purchased from them they will not support any resolution attempt. Legacy boot mode does not normally support partitions greater than 2TB in size, and can cause data loss or other problems if you try to use it normally.