Reinstall the grub - so it'll work
If the GRUB is causing problems and you can no longer boot into your system, you must reinstall the boot loader. Fortunately, this is quick and easy to do with a live CD. If you can start your Linux system, it is even easier - in this case jump to the last section.
Reinstall the grub - create and start the live CD
Since a faulty GRUB can no longer be started into the system, you need a live CD or a bootable USB stick with a suitable medium.
- Create boot CD: Download a Linux image such as Ubuntu and create a bootable DVD with the ISO file.
- Alternatively, you can also use a bootable USB stick, for example via the Linux Live USB Creator (see screenshot).
- Then insert the CD into the drive or connect the USB stick and start the medium via the BIOS.
Reinstall the grub - start the live CD and repair the boot loader
- Once the Ubuntu Live CD has started completely, select "Try it out" to be able to use the system immediately.
- Start the "GParted" program via the applications. If it is not yet installed, do this first with the terminal command "sudo apt-get install gparted".
- In the program you can read which partition is your system partition. Usually it is / dev / sda1 or / dev / sda2. If you are new to GParted, another article will show you how to use the partition tool correctly.
- Open via Applications -> Accessories -> Terminal. Alternatively, use the key combination [Ctrl] + [Alt] + [T].
- Now enter the following commands one after the other and confirm each with the Enter key:
- sudo -i
- mkdir / syares
- mount / dev / sdaX / syares [IMPORTANT: replace "X" with the respective number of the system partition, eg "/ dev / sda2"]
- mount -o bind / dev / syares / dev
- mount -o bind / proc / syares / proc
- mount -o bind / sys / syares / sys
- chroot / syspar
- update-grub
- grub-install / dev / sda
- exit
Now you can shut down your PC, remove the live CD and restart your system as usual using the GRUB that is working again.
System still bootable - simply reinstall GRUB
If you can still start your Linux system without any problems, the GRUB can be reinstalled at lightning speed:
- Open the terminal via Applications -> Accessories, or with [Ctrl] + [Alt] + [T].
- Enter "sudo grub-setup / dev / sda", confirm with your password and press the Enter key.
- For a complete reinstallation use the command "sudo grub-install / dev / sda".
- Finally, update the GRUB config file with the terminal command "sudo update-grub" and confirm again.
- Restart the computer.
Tip: We show you clearly in our picture gallery how to configure GRUB correctly.