How To Reinstall Grub2 Ubuntu

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Have you ever encountered a situation where your Ubuntu system fails to boot due to a grub2 error? Don’t worry, I’ve been there too. In this article, I’ll guide you through the process of reinstalling grub2 in Ubuntu, sharing my personal experiences and providing detailed instructions along the way.

Understanding Grub2

Grub2 (GRand Unified Bootloader version 2) is a bootloader, the first software that runs when you turn on your computer. It helps the computer find the operating system and load it into memory.

As an Ubuntu user, I appreciate the flexibility and power that grub2 provides. However, just like any other software, it can sometimes encounter issues. When this happens, it’s important to know how to reinstall grub2 to get your system back up and running.

The Reinstallation Process

Before we start, make sure you have a bootable Ubuntu installation USB or DVD handy. This will be essential to reinstall grub2.

Step 1: Booting from the Ubuntu Installation Media

Insert the bootable Ubuntu installation media into your computer and restart it. Make sure your computer is set to boot from the installation media. This can usually be changed in the BIOS settings of your computer.

Once the installation media is booting, you will see the Ubuntu installation menu. Select the option to “Try Ubuntu without installing.”

Step 2: Mounting the Ubuntu Partition

Once you’re in the live environment, open a terminal. We need to identify the partition where Ubuntu is installed. Type the following command:

sudo fdisk -l

This command will list all the partitions on your system. Look for the partition with the Linux file system (usually ext4 or ext3) and note down its device name (e.g., /dev/sda1).

Next, mount the Ubuntu partition by running the following command:

sudo mount /dev/sda1 /mnt

Replace /dev/sda1 with the device name of your Ubuntu partition.

Step 3: Mounting Additional Partitions

Depending on your setup, you may need to mount additional partitions, such as the EFI System Partition or a separate /boot partition. If you’re unsure, you can skip this step and proceed to the next one.

To mount additional partitions, use the following commands:

sudo mount /dev/sda2 /mnt/boot

Replace /dev/sda2 with the device name of the partition you need to mount.

Step 4: Reinstalling Grub2

Now we can reinstall grub2. Run the following command:

sudo grub-install --boot-directory=/mnt/boot /dev/sda

This command will install grub2 to the specified boot directory and device, replacing any existing installation.

Step 5: Updating Grub Configuration

Finally, we need to update the grub configuration file. Run the following command:

sudo update-grub

This command will scan your system for installed operating systems and generate the grub configuration file accordingly.


Reinstalling grub2 in Ubuntu might seem like a daunting task, but with the right instructions and a bit of patience, you can solve boot-related issues and get your system back on track. Remember to have a bootable Ubuntu installation media on hand, follow each step carefully, and don’t hesitate to seek help if needed.

By following the steps outlined in this article, you should now be able to reinstall grub2 in Ubuntu successfully. Hopefully, this guide has helped you gain a better understanding of the process and provided a solution to your grub2-related issues.