How to fix 'error: unknown filesystem. grub rescue'

This step-by-step tutorial will show you how to fix the 'error: unknown filesystem. grub rescue' problem in Ubuntu and Linux Mint.

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

This tutorial will show you how to fix this problem by repairing grub in Linux Mint and Ubuntu.


How to repair GRUB

error: unknown filesystem.
grub rescue>

  1. Type the following command: 
    
ls
  2. Press the Enter key on your keyboard.

This command will show all the partitions on your hard drive.

Example 1:


grub rescue> ls (hd0) (hd0,gpt5) (hd0,gpt4) (hd0,gpt3) (hd0,gpt2) (hd0,gpt1) (fd0) grub rescue>

Example 2:


grub rescue> ls (hd0) (hd0,msdos5) (hd0,msdos4) (hd0,msdos3) (hd0,msdos2) (hd0,msdos1) (fd0) grub rescue>
  1. To find the partition where Linux Mint or Ubuntu is installed, type the following command: 
    
ls (hd0,...)
  2. Press Enter.

Do this for every 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>

In my example is (hd0,gpt5) 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 your partition.

  1. Type the command below but replace gpt5 with your partition. 
    
set prefix=(hd0,gpt5)/boot/grub
  2. Press Enter.
  3. Type the command below but replace gpt5 with your partition. 
    
set root=(hd0,gpt5)
  4. Press Enter.
  5. Type the following command: 
    
ls /
  6. Press Enter.
  7. Type the following command: 
    
insmod normal
  8. Press Enter.
  9. Type the following command: 
    
normal
  10. Press Enter.
  11. The Grub will now open a boot menu and display all installed operating systems. Boot into Linux Mint or Ubuntu.
  12. Open a Terminal window.
  13. Type the following command: 
    
sudo update-grub
  14. Press Enter.
  15. Type the following command: 
    
sudo grub-install /dev/sda
  16. Press Enter.
  17. Close the Terminal window.

This solution fixed my problem.

Linux