1

left my laptop at night and it apparently downloaded the new Windows 10 fall creators update (I have dual boot), after the restart it sent me to grub rescue which I though I'll solve like people solved this issue with past windows updates, but couldn't find any partition, I tried using LiveUsb to see the disk, and indeed the files seem to be still there, but the linux partition seems to have been erased.

In this link there seems to be an solution, at least to save some files with testdisk, where they say that recovery is possible but tricky, I have a external hard drive on which I'd like to recover my files before I nuke install again, leaving windows 10 behind, it's being a totally horrible experience.

Anyone else having the same issue with the new fall update? How did you proceed?

UPDATE 1: Managed to get the Windows part working after using the Windows recovery usb like mentioned in this video. After I am done backing up my data I'll see if I can recover the linux partition and save my files.

Also here is the pasty of my partitions.

Lesson of the day: Back up your data, I had the scare of a lifetime.

  • 1
    Welcome to askubuntu! Perhaps a pastie of your existing partition table (output of sudo parted -l ) edited into your post would help us help you. Thank you. – Elder Geek Oct 3 '17 at 20:28
  • Hi there, sorry about that, here it is the link to it – bpinaya Oct 3 '17 at 20:30
  • Please edit it into your post. Comments can be deleted here for several reasons. – Elder Geek Oct 3 '17 at 20:34
  • Use parted rescue or testdisk. Windows since Windows 7 on major updates rewrites partition table, but "forgets" to include Linux partitions.askubuntu.com/questions/654386/… Parted rescue seems easier than testdisk askubuntu.com/questions/665445/… – oldfred Oct 3 '17 at 21:47
  • yes the creators update deletes linux partition, this however doesn't erase data. testdisk or other partition recovery programs can rewrite the partition table to put the partitions back. It has to be a linux recovery tool since windows does not recognize linux partitions, which is why the update deleted them. – ravery Oct 3 '17 at 21:49
2

I received the following boot error on an Ubuntu 16.04/Windows 10 dual boot PC after the Windows 10 Fall Creators Update was installed automatically by Microsoft;

    error: unknown filesystem
    Entering rescue mode
    grub rescue> _  

I solved it by a) running Ubuntu using the live CD (Ubuntu 16.04 installation disc) and b) reinstalling grub.


a) Run Ubuntu using the live CD:


Warning: modifying the bios can damage your system

  1. Ensure that your computer's bios is set to boot from the optical media drive first (if a disc is inserted)
  2. Insert Ubuntu Live CD, and restart computer
  3. Choose to start Ubuntu using the live CD (don't reinstall Ubuntu)
  4. If the Ubuntu live session is buggy (for example the compiz graphical user interface flashes), then ignore the user interface and open up a terminal directly (e.g. Ctrl-Alt-F3). Login to the terminal using username ubuntu and no password.

b) Reinstall (Repair/Restore) Grub:


I followed these instructions (from http://howtoubuntu.org/how-to-repair-restore-reinstall-grub-2-with-a-ubuntu-live-cd);

Warning: Using the sudo command, especially from a Live CD can do serious damage to your system. Read all instructions and confirm you understand before executing any commands. When pasting into the Terminal, use Ctrl+Shift+V, NOT Ctrl+V.

  1. Find out what partition your Ubuntu Installation is on. It is usually an EXT4 (linux) Partition. Here are some methods to do this;

    • i) GParted

      • launch GParted (included in the Live CD)
      • Find out the Ubuntu partition (sdXY)
    • ii) fdisk

      • sudo fdisk -l
      • Find out the Ubuntu partition (sdXY)
    • iii) Terminated Ubuntu Installation [NOT RECOMMENDED]

      • Use live CD and select to "Install Ubuntu" (without actually installing Ubuntu);
      • [Welcome] Choose the language you wish to perform the installation and click on Continue button to proceed further.
      • [Preparing to Install Ubuntu] Next, leave both options from Preparing to Install Ubuntu unchecked and hit on Continue button again.
      • [Installation Type] Check the Something else option and hit on Continue button to proceed further.
      • Find out the Ubuntu partition (sdXY)
      • Click Quit
  2. Mount the partition your Ubuntu Installation is on. Replace the XY with the drive letter, and partition number, for example: sudo mount /dev/sda1 /mnt.

    sudo mount /dev/sdXY /mnt
    
  3. Now bind the directories that grub needs access to to detect other operating systems, like so.

    sudo mount --bind /dev /mnt/dev &&
    sudo mount --bind /dev/pts /mnt/dev/pts &&
    sudo mount --bind /proc /mnt/proc &&
    sudo mount --bind /sys /mnt/sys
    
  4. Now we jump into that using chroot.

    sudo chroot /mnt
    
  5. Now install, check, and update grub. This time you only need to add the drive letter (usually a) to replace X, for example: grub-install /dev/sda, grub-install -recheck /dev/sda.

    grub-install /dev/sdX
    grub-install --recheck /dev/sdX
    update-grub
    
  6. Now grub is back, all that is left is to exit the chrooted system and unmount everything.

    exit &&
    sudo umount /mnt/sys &&
    sudo umount /mnt/proc &&
    sudo umount /mnt/dev/pts &&
    sudo umount /mnt/dev &&
    sudo umount /mnt
    
  7. Shut down and turn your computer back on, and you will be met with the default Grub2 screen.

This enabled grub to load properly and boot into Ubuntu. To enable grub to boot into Windows again, I had to c) detect the Windows partition and reupdate grub (from GRUB does not detect Windows);


c) Detect the Windows partition and reupdate Grub:


  1. Detect the Windows partition:

    sudo os-prober
    
  2. Reupdate grub:

    sudo update-grub
    
  • (I have added the grub restoration instructions inline) – user2585501 Nov 30 '17 at 8:42
  • "Warning: modifying the bios can damage your system"? Since when? How? With all due respect this doesn't parse at all. Certainly simply changing the boot order as you suggest won't damage anything. If you are trying to dissuade people from overclocking, it might be best to say so. As it is, it's unlikely that anyone who doesn't have the experience will ever get to the b section of your instructions. Furthermore && is used between instructions and serves no purpose at end of command line. See serverfault.com/q/53577 – Elder Geek Feb 21 '18 at 23:39

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.