Currently I'm running Windows 10 in UEFI mode, and I would like to add Ubuntu in a dual boot.

However, my PC will not boot from my USB drive in UEFI mode (even with secure boot disabled), only in legacy.

So I was thinking, what if I install Ubuntu in another partition using legacy mode and change Ubuntu to UEFI after it's installed? Is this a good idea, or will it screw up my dual boot config?

Thanks, in advance

  • 1
    Have you checked this? It's marked as solved....ubuntuforums.org/showthread.php?t=2333020 Feb 15, 2018 at 11:38
  • It is easier to convert if you use Boot-Repair booted in UEFI mode to convert. You can manually install the UEFI version of grub and convert to UEFI. You also can boot just from UEFI boot menu, if both are not UEFI. But then cannot use grub to dual boot as grub can only offer to boot other installs in same boot mode.
    – oldfred
    May 20, 2018 at 3:29

1 Answer 1


It won't screw it up, I recommend doing it like this, I'm currently running Windows 10 on UEFI and Ubuntu 17 on legacy and everything works fine, my laptop BIOS lets me choose which one to run by default so I can choose the one I use mostly at any time and not worry about choosing OS Everytime it boots up.

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