Windows 10/ Ubuntu dual boot suddenly doesn't give option to boot into ububtu

Question

I have a dual-booted pc with windows 10 and ubuntu 14.04, which has been working just fine for a few months now. I noticed yesterday, however, that now when I restart my computer it boots straight to windows without showing me the grub menu. Secure boot is still disabled. I don't know if this is related to a windows update or what, but help in resolving the issue would be most welcome.

A windows update probably set windows first in the boot order. Check that in the efi (bios) settings when you reboot. If so, all you need to do is put ubuntu back as first in the boot order. — chaskes, Nov 05 '15 at 13:32

score 0 · Answer 1 · answered Nov 05 '15 at 13:55

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You can try to repair the grub by using boot-repair-disk. It would repair the grub, provided Ubuntu is not corrupted.

answered Nov 05 '15 at 13:55

Venu

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This approach is overkill, and runs the risk of creating new problems. In all probability, a Windows update simply set the Windows boot loader as the default, which can be fixed with EasyUEFI in Windows (or efibootmgr in Ubuntu). – Rod Smith Nov 05 '15 at 14:05

cl-netbox · Answer 2 · 2015-11-05T14:30:33.910

Maybe a "bigger" Windows update did reset your energy settings configuration
or it somehow "changed" or "damaged" something within the EFI boot partition.

First attempt to bring everything back to normal behaviour :

Boot into BIOS and select Ubuntu in UEFI settings to be the default system to boot.

Restart the computer - when everything is fine now you're done - if not - second attempt :

Boot into Windows and disable hibernation and Fast Boot.

To disable hibernation open command prompt as administrator and execute :

powercfg /h off

To disable Fast Boot open Control Panel (the old version - not the modern design),
select the Energy Settings, enable show hidden settings and uncheck Fast Boot.

After having done this shutdown the machine completely - do NOT reboot !

Start the computer - when everything is fine now you're done - if not - third attempt :

Reinstall the GRUB boot loader to your Ubuntu installation in EFI mode.
Boot from the Ubuntu installation media - open a terminal and execute:

    sudo mount /dev/sd*** /mnt
    sudo mount /dev/sd** /mnt/boot/efi
    for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
    sudo chroot /mnt
    grub-install /dev/sd*
    update-grub

Note:

sd* = disk | sd** = efi partition | sd*** = system partition

To identify the partition numbers use GParted - it is included in the Ubuntu installation media.

Boot into BIOS and select Ubuntu in UEFI settings to be the default operating system to boot.

Chances are the final sentence/paragraph of this answer is all that's required -- but many EFIs have such poor user interfaces that it's not possible to do it in this way. That's why I suggested EasyUEFI in Windows; Windows boots now and EasyUEFI will probably do the job with minimal fuss. — Rod Smith, Nov 05 '15 at 14:08

score 0 · Answer 3 · answered Nov 05 '15 at 14:04

Download and install EasyUEFI in Windows, then run it. The program should give you a list of boot options, at least one of which should be for Ubuntu. Use EasyUEFI to move the Ubuntu item to the top of the list. That should restore Ubuntu to bootability.

Windows 10/ Ubuntu dual boot suddenly doesn't give option to boot into ububtu

3 Answers3