System: Dell XPS 8700 running Windows 8.1 using secure boot and UEFI.

Boot Info Summary

I installed Ubuntu on a USB flash drive using the Live CD version. My goal was to keep the Dell untouched and have Ubuntu on a removable flash drive that I could plug into the computer, hit the appropriate key on my computer at power on to get a list of boot options and then choose Ubuntu when I wanted to run Ubuntu. Otherwise, with the flash drive removed, the computer would run Windows 8.1 as before

To install Ubuntu, I created an EFI system partition on the flash drive (sdf1) and explicitly specified during installation that the Grub files be installed there (sdf1) and not on my Windows drive (sda).

Everything works fine if I have the flash drive with Ubuntu plugged in and turn on the computer. Grub comes up with a menu of boot options including Windows and both Ubuntu and Windows run fine. The problem is that if I remove the flash drive from the computer, then instead of booting Windows I get a Grub rescue command prompt.

  1. What do I need to do to get the Dell computer back to it's original state where it boots Windows as it did before using the Windows bootloader? I've researched the problem and tried most of the things on the Windows end (running Windows repair (get a message that Windows can't repair, see log), booting to a command prompt and running bootrec fixboot scanos (which returned no O/S found) and such).

  2. Once I've fixed the computer, can I copy the boot files in sda2 to sdf1 in order to be able to get my flash drive to boot when plugged into the computer? This is not a big deal as I can live without the Ubuntu; my primary concern is getting the computer back to booting Windows.

It seems like things are working as they should (other than the fact that the Ubuntu boot files got installed on sda2 instead of sdf1 as I specified) so there should be no "bugs" or guesswork in any of this--just a question of understanding what the Ubuntu install did.

  • You should run /bootrec /fixmbr from Windows recovery disc. This will rewrite GRUB loader to plain old Windows MBR. This is often enough to restore normal Windows boot.
    – Danatela
    Commented Sep 16, 2014 at 2:46
  • As I mentioned in my post, I have tried running the various /bootrec commands such as /fixmbr.
    – dss1873
    Commented Sep 18, 2014 at 22:09

1 Answer 1


It turned out to be a simple fix (to restore the ability of the system to boot Windows when the Ubuntu flash drive is not plugged in).

I went to BIOS and chose to reload the default settings. That made the Windows boot manager show up once again and everything is back to working the way it was.

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