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The GNU project has a bootloader called GRUB, which stands for “Grand Unified Bootloader.” A bootloader is very important because an operating system can’t start up without it. It’s the first thing that runs when the computer is turned on. The bootloader gives control to the kernel of the operating system. In this error, GRUB is a boot loader that loads configuration information at startup and lets you change it at startup. This means that the computer can’t start up when the error happens. So, if the error “grub rescue unknown file system” shows up, it means that the computer is having trouble starting up.
So, what makes the boot problem happen? After looking into it, we found that the problem happens when people make changes to the two operating system partitions on the same hard disc (like deleting the system partition, resizing a partition, reinstalling Ubuntu OS, etc.). If you do any of these things, the boot file might get lost or moved, and GRUB won’t be able to find the original partition where the boot file is.
Ways to Fix GRUB Unknown Filesystem Error
Use a Windows bootable USB stick
- Start Windows 10 from the installation media and select the “Repair Computer” option.
- click the “Troubleshoot” tab and select “System Restore” to reset the computer to the restore point you set up earlier.
- You can also try the “Automatic Repair” option.
- if that does not work, you need to choose the “Command Prompt” option.
- Then type the following commands one after another at the command prompt to recreate the MBR.
“bootrec /fixmbr”“bootrec /fixboot”“bootrec /scanos”“bootrec /rebuildbcd”
Enter grub mode to fix grub
- You need to find out which partition your Linux is on and where the grub directory is. It would be better if you still remember it, but it doesn’t matter if you forget.
- Type “grub rescue>ls” and press “ENTER” to list all the disks and partitions. For example, hd0,(hd0, 1)//,(hd0, 4),(hd0,7),(hd0,8),(hd0,9)….
- Type “grub rescue>ls (hd0,0)/grub” and press “ENTER“. Repeat this step and try each partition one by one until the content of the partition appears instead of “unknown filesystem”.
- Assume that at (hd0,8) the contents are successfully displayed.
- type “grub rescue>set root=(hd0,8)” and press “ENTER“.
- type “grub rescue>set prefix=(0,8),grub” and press “ENTER“.
- type “grub rescue>insmod/grub/normal.mod” and press “ENTER”. Now you have exited grub rescue mode and entered grub mod, which you should be familiar with.
- type “grub>normal” and press “ENTER“.
- after entering Linux, type “sudo update-grub” at the command line to fix grub.
- type “sudo grub-install/dev/sda”. //sda is your boot disk.
GRUB Features
About
Final Words
This is yet another “geeky” post by someone who has been writing a lot about Hyderabad and its food for a long time. But, on the other hand, we usually write a post when we have a new, strange, or interesting experience. Right now, I’m having one while installing Windows 10 Technical Preview 64bit on my tiny HP Mini. Most of us know that the tech giant has already given a technical preview to customers all over the world, along with a warning about the risks of installing it on your systems, but we still got my hands on this one. We hope our article on “How to Fix GRUB Unknown Filesystem Error” will surely help you to do so.