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Grub rescue - error: unknown filesystem

I have a netbook with a dualboot for Windows7 and Ubuntu. I accidentally deleted the partition for Ubuntu then after I restart my netbook it goes directly to the error: unknown filesystem grub rescue>.

I have read some of the threads but most of them require a LiveCD. Is there a way to fix this error without using a LiveCD?

I have an installer of Ubuntu on a flash drive will that one work since I don't have a DVD ROM available?


You can simply reinstall Ubuntu from USB on deleted partition space.

Another way of acting is to recover deleted partition using "TestDisk" for example.

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You can install GRUB on your hard disk. You can do this by using putting the LiveCD on a flash disk ( How can I make a Ubuntu Live USB with Ubuntu, GParted & HBCD? )

  1. Boot to the Flash Disk. When you get the Ubuntu Live Desktop, Open terminal ( What is a terminal and how do I open and use it? ) and type the following:

    sudo grub

    This will get you a grub> prompt (i.e. the grub shell).

  2. At grub>. enter these commands

    find /boot/grub/stage1

    This will return a location. If you have more than one, select the installation that you want to provide the grub files.

  3. This is important: what was returned for the find command use it in the next line for the "?" -

    root (hd?,?)

    Again use the value from the find command i.e. if find returned (hd0,1) then you would enter root (hd0,1)

  4. Next enter the command to install grub to the mbr

    setup (hd0)
  5. Finally exit the grub shell


Now you are done. Reboot the machine.

Another option is to run this command:

grub-install /dev/hda
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  • grub not installed and somehow I'm unable to install it on my Ubuntu 12.04 livecd. – Almaron Dec 13 '13 at 18:17

No. You must fix it with LiveCD because You deleted GRUB which is responsible for booting system.

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  • I have an installer of Ubuntu on a flashdrive will that one work since I don't have a dvd rom available? Thanks – treszjaloom Jul 28 '12 at 0:01
  • When you boot flashdrive select Try Ubuntu instead of Install in boot options – zuberuber Jul 28 '12 at 0:09
  • 2
    GRUB is installed in the MBR, but that just transfers control to GRUB as installed in Ubuntu's /boot directory. If the Ubuntu system is gone, GRUB is won't work. You might be able to boot the Windows system by giving all the right commands on the boot menu to chain-load into the Windows boot loader, but what you really need to do is install some self-contained boot loader to the MBR. syslinux will do this, and you can install it from the Ubuntu live USB, but I'm haven't done it and don't know how. Hopefully someone will post an answer about this; otherwise, I might look into it myself. – Eliah Kagan Jul 28 '12 at 2:03
  • Can you give more details on what needs to be done? – nanofarad Aug 16 '12 at 13:20

grub rescue> is happening because you deleted Ubuntu, and along with it the /boot folder, which contains vital files. You must use a LiveCD to install a bootloader - either GRUB, or use the Windows CD to reinstall the Windows bootloader. I suggest LILO (Linux Loader), but like the fellow who suggested syslinux, I am not sure how to install it. There are Ubuntu docs which document this, I believe - and lots of forum threads. @AthloX: GRUB IS installed on the MBR, just has no /boot.

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