1

I installed Ubuntu 14.04 as a dual boot with Windows 8 (from Win8). The installation went well without any issues.

When I switch my laptop ON, it opens the GRUB menu with :

  • Ubuntu
  • Advanced options for Ubuntu
  • Windows 8 (loader) (on /dev/sda1)

Ubuntu loads without any issue but, when I select Windows 8 I constantly come back to the GRUB menu. I reinstalled GRUB but nothing changes.

I checked in BIOS and found that the boot mode is LEGACY. When I swap it to UEFI, save and exit, I get this message :

" Default Boot Device Missing or Boot Failed. Insert Recovery Media and Hit any Key. Then select 'boot manager' to choose a new Boot Device or to Boot Recovery Media ".

When I restart the laptop after getting this message, I come back to the LEGACY mode and return to the starting point : Ubuntu loading, Windows doesn't.

So. Any suggestion to fix this?

Here is the pastebin : http://paste.ubuntu.com/13397045/

Thanks a lot for any help

Best

2

Here are some key points (out of order) from your Boot Repair output:

/dev/sda1    *          2,048   669,571,071   669,569,024   7 NTFS / exFAT / HPFS

In other words, Windows is on /dev/sda1. There are other lines that confirm this, including the next ones, which are important for other reasons....

sda1: __________________________________________________________________________

    File system:       ntfs
    Boot sector type:  Grub2 (v1.99-2.00)

In other words, GRUB is installed in the boot sector of /dev/sda1, your Windows partition. This is highly irregular at best, and really is the source of the problem; but to complete the loop, as it were....

menuentry 'Windows 8 (loader) (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-B6F60302F602C29B' {
    insmod part_msdos
    insmod ntfs
    set root='hd0,msdos1'

This fragment of your GRUB configuration confirms that GRUB is trying to launch the boot loader on /dev/sda1 (hd0,msdos1 in GRUB-speak) for Windows. Ordinarily this would work, but because that partition holds GRUB instead of the Windows boot loader, you end up in the endless loop you describe.

Chances are this problem arose because you told Ubuntu to install GRUB to /dev/sda1 at some point. This was a mistake, but if you did this through the Ubuntu installer, it's arguably a bug that the installer accepted this location, which it could (and arguably should) detect as an invalid option and refuse to accept, or at least warn you of the danger. If you think this is what happened, you should probably file a bug report to encourage changes that would prevent this sort of thing from happening to others (or to yourself!) in the future.

As to fixing it, I'm afraid that you'll have to use Windows tools for this job. I'm not an expert on repairing Windows in this way, so unless somebody else chimes in with details, you may do well to post to a Windows forum. The key is that you need to restore the Partition Boot Record (PBR) for the first partition. Ideally, you do not want to touch the Master Boot Record (MBR); however, there's a good chance that your Windows repair will replace the MBR as well as the PBR. If this happens, you'll need to run Boot Repair again to re-install GRUB to the MBR.

  • Thanks Rod for your help! I now have a place from where to start to try fix all this mess! Thank you – JeremieB Nov 22 '15 at 13:49

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