I installed Windows 7 on my external hard drive, and it was working fine. It was booting up, and I was actually able to go online and install programs on it.

But then when I try to take out the internal hard drive that was originally there thinking that it is not needed anymore since I can use my USB 3.0 external hard drive as my main hard drive, it would not work, and the next time I try to boot up the computer, the USB external hard drive would not even show up in the BIOS boot media selection menu.

How can I boot Windows from an external hard drive?

  • are you able to detect bootable usb memory sticks in the BIOS boot menu? if not, you might have to enable the usb-devices in the BIOS settings. should be somewhere at (advanced) chipset control, look for USB Configuration or USB Features. – kindaleek Dec 6 '14 at 13:55
  • Wouldnt disabling the internal sata controllers and removing anything internal from the boot order work? – user396554 Dec 6 '14 at 14:05
  • I wonder how did you manage to install Windows on an external HDD. I heard MS only allows installing on sata-connected HDDs. May be a problem with USB3 though. Does your motherboard even support USB3? The last option is to disassemble the external HDD and connect it to sata in your PC. – redbeam_ Apr 15 '15 at 12:50
  • I've got the answer to this (I even have 101 reputation but it won't let me answer). Since you're using USB 3, you need to ensure that the USB drivers are loaded by enabling Boot Flag 0x000014 in regedit. You also need to make sure, as others suggested, that your bios has USB as a bootable option. The boot flag I mentioned is under HKLocalMachine -> HWConfig. By default it's usually 0x000000 or 0x000001 – mystic cola Jun 28 '16 at 20:02

protected by Community Dec 6 '14 at 14:47

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