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Thread: Unable to boot on windows after boot-repair

  1. #1
    Join Date
    Jun 2017
    Beans
    4

    Unable to boot on windows after boot-repair

    Hi,

    I hope someone can help with boot of my system. Ihave been running for quite some time kubuntu and windows without issues. However, some time ago the boot partition got too full with too many kernel versions (I didn't do a proper maintance to keep it clean) which leads to issues. Anyhow, I did a clean up of the boot partition and then grub failed. I ran boot-repair and I got kubunt running up again, however, windows is not showing up. I tried several options of boot-repair without success.

    I have added an entry on the /etc/grub.d/40_custom file, but it is not working.

    Here is the report from boot-repair:
    https://paste2.org/KknM8cWh

    I think I try many of options in boot-repair, I have run "testdisk" which says that the MBR of windows is ok. But I don't know how to make it work.

    Currently, when I select the windows 10 (the addition entry), I get something like:
    "error: can't find command 'ntldr'.

    and it goes back to the grub menu.

    Any help will be greatly appreciated!

    Thanks

  2. #2
    Join Date
    Jun 2014
    Beans
    4,596

    Re: Unable to boot on windows after boot-repair

    I would open a terminal and run: sudo update-grub to start with. The entry you have for windows 10 is incorrect. The ntldr won't work because that boot file has not been used with windows since xp. You also need a chainloader at the beginning of the entry. Best try update grub to see what happens. If that still fails, post the output after running boot repair again or the output of the update-grub command.

  3. #3
    Join Date
    Jun 2017
    Beans
    4

    Re: Unable to boot on windows after boot-repair

    Hi,

    Thanks a lot for your reply. I ran just
    sudo update-grub
    and although it seems to be running something, still not working.
    This is the new report
    https://paste2.org/IFNHeknI

    Sorry for the probably quite basic question, but I'm not familiar enough with grub and the entries. How should it look like? Do you have an example?

    Thanks

  4. #4
    Join Date
    Jun 2014
    Beans
    4,596

    Re: Unable to boot on windows after boot-repair

    Your boot repair output does not show an entry for windows in the grub.cfg menu you posted. If you put an entry in the 40_custom file, you need to run: sudo update-grub afterward to get it into the grub.cfg file which you see on boot. Either that or just for testing purposes, you can put the entry directly in the grub.cfg file but if you do that, then do NOT run update-grub.

    You have Grub installed on the MBR of the first drive (1.8TB). Is that set to first boot priority in the BIOS?
    Your window entry in 40_custom does not have double quotes at the end of the menuentry line so it probably won't show on the menu unless you add them.
    I'm not sure where you got the UUID entry you have in the menu. The UUID for your windows partition (sda2) is: 053E59C545BEDECE
    You might try changing that.
    Although the ntldr boot files hasn't been used on recent windows releases, it appears from some reading I have done that the command can be used in a boot file (grub.cfg). I would try the entry below, either by putting it in grub.cfg and NOT updating grub or putting it in 40_custom and running update-grub.

    menuentry "Windows 10 Test" {
    insmod part_msdos
    insmod ntfs
    set root='(hd0,msdos2)'
    search --no-floppy --fs-uuid --set=root 053E59C545BEDECE
    chainloader +1
    }
    If that fails, you might try adding insmod ntldr on the line below insmod ntfs and replace the chainloader line with ntldr ($root)/bootmgr

    Good luck.

  5. #5
    Join Date
    Jun 2017
    Beans
    4

    Re: Unable to boot on windows after boot-repair

    Hi,

    I tried both method an none of them has been successful. During the attempts I broke again grub and I had to rerun boot-repair again. Here is the latest report

    https://paste2.org/EtaGGnjI

    Now, when trying to boot "windows 10 test", I get:
    '/grub/x86_64-efi/ntldr.mod' not found

    Still quite lost in this. Thanks a lot for all the help and suggestions so far. Any other advice?

    Thanks

  6. #6
    Join Date
    Mar 2011
    Location
    Idaho
    Beans
    293

    Re: Unable to boot on windows after boot-repair

    When you installed MS Windows and linux , you was booted in legacy/MBR mode. When you booted boot-repair it was booted in EFI mode and converted the linux grub for EFI booting. When that was done , you can not use grub to boot MS Windows (legacy installed). You will need to be sure to boot 'boot-repair' in legacy mode and change grub booting back to legacy boot. I do not know for sure the steps needed when one has both MBR and GPT hddls , so will let others tell you how to proceed with repair.

  7. #7
    Join Date
    Jun 2017
    Beans
    4

    Re: Unable to boot on windows after boot-repair

    Hi,

    Thanks for all the replies, I've trying without success to follow the recommendations, but still not working. So, I'm trying to learn a bit more of the process, to see if I could run it manually, but I don't feel confident yet.

    However, something that kind of bothers me is that boot-repair it does points of find windows on the list. How is it not able to add it to the menu?



    Thanks a lot

  8. #8
    Join Date
    Jun 2009
    Location
    SW Forida
    Beans
    Hidden!
    Distro
    Ubuntu 16.04 Xenial Xerus

    Re: Unable to boot on windows after boot-repair

    New UEFI based systems also have BIOS boot mode.
    But once you start booting in one mode, you cannot switch to another mode, or grub only boots other installs in same boot mode as you started to boot grub/Ubuntu.
    Best to always be consistent and install all systems in UEFI boot mode, or all systems in BIOS boot mode.

    You can boot Ubuntu in BIOS/CSM/Legacy boot mode from a gpt partitioned drive if you add a tiny 1 or 2MB unformatted partition with the bios_grub boot flag. And then install grub to gpt's protective MBR, often easiest with Boot-Repair. You may want other boot loaders on other drives, so with multiple drives do not run Boot-Repair's auto fix. Only use Advanced mode and choose operating system and drive.

    You can dual boot in different boot modes, but only using UEFI boot menu, often f10 or f12.
    And I believe rEFInd will allow booting in different modes. It may use UEFI one time reboot configuration to switch boot modes, and reboot into other install. Only installs in UEFI system, but can then boot a BIOS system.
    http://www.rodsbooks.com/refind/
    http://www.rodsbooks.com/efi-bootloaders/
    For more info on UEFI boot install & repair - Regularly Updated :
    http://ubuntuforums.org/showthread.php?t=2147295
    Please use Thread Tools above first post to change to [Solved] when/if answered completely.

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