How to Fix: error: unknown filesystem. grub rescue> in Linux Mint & Ubuntu

Fix error: unknown filesystem. grub rescue>

Do you get this error: unknown filesystem.
grub rescue>
error message when you start your computer?

Then you've come to the right place, because this tutorial will show you step by step how to repair grub in Linux Mint and Ubuntu.

How to Repair GRUB

error: unknown filesystem.
grub rescue>

  1. Run the following command: ls
    • Example: grub rescue> ls
    • This command will show all the partitions on your hard drive.
    • Examples:
    • grub rescue> ls
      (hd0) (hd0,gpt5) (hd0,gpt4) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (fd0)
      grub rescue>
    • grub rescue> ls
      (hd0) (hd0,msdos5) (hd0,msdos4) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (fd0)
      grub rescue>
  2. Now you will need to find the partition where Linux Mint or Ubuntu is installed. To do this, run the following command: ls (hd0,...) for each partition until you see something, like:
    • grub rescue> ls (hd0,gpt5)/
      ./ ../ lost+found/ etc/ media/ bin/ boot/ dev/ home/ lib/ mnt/ opt/ proc/ root/ run/ sbin/ selinux/ srv/ sys/ tmp/ usr/ var/ initrd.img initrd.img.old vmlinuz cdrom/
      grub rescue>
    • (hd0,gpt5) is in my example the correct partition and I'll be using this partition as an example in the following steps, so don't forget to replace gpt5 with the correct partition.
  3. Run the following command: set prefix=(hd0,gpt5)/boot/grub
  4. Run the following command: set root=(hd0,gpt5)
  5. Run the following command: ls /
  6. Run the following command: insmod normal
  7. Run the following command: normal
    • The Grub will now open a boot menu and display all installed operating systems.
  8. Boot into Linux Mint or Ubuntu.
  9. Open a Terminal.
  10. Run the following command: sudo update-grub
  11. Run the following command: sudo grub-install /dev/sda
  12. Close the Terminal.

This fixed my problem and hopefully it will also fix yours.

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