how to repair grub

How do I fix a corrupted grub?

The solutionTo fix the problem execute from grub command line: ... Restore boot partition on hd0,0 (first partition on first disk) as in above example from find command. ... Then setup grub on first disk (hd0) – as in above example boot stage1 is located on hd0. ... After command will succeed reboot the server.

How do I fix grub in terminal?

via Partition Files CopyBoot to the LiveCD Desktop.Mount the partition with your Ubuntu installation. ... Open a terminal by selecting Applications, Accessories, Terminal from the menu bar.Run the grub-setup -d command as described below. ... Reboot.Refresh the GRUB 2 menu with sudo update-grub.More items...•

How do I fix grub live?

How to Repair GrubBoot to the live cd or USB that you have and open a terminal window( Ctrl + T ) and type the following: sudo fdisk -l.Now you are sure about where to install grub. ... sudo mount /dev/sda3 /mnt , where /mnt is any directory you need.More items...•

How do I restore grub loader?

To remove it:Hit Windows + X and select Disk Management .Find the Ubuntu partition. It will probably be a large partition without a drive letter.Be sure you have the correct partition!Right-click the partition and delete or reformat it with a Windows filesystem.

How do I run boot repair?

Method 1: Startup Repair toolStart the system to the installation media for the installed version of Windows. ... On the Install Windows screen, select Next > Repair your computer.On the Choose an option screen, select Troubleshoot.On the Advanced options screen, select Startup Repair.More items...•

How do I uninstall and reinstall GRUB?

Uninstalling GRUB 2Open a terminal: Applications, Accessories, Terminal.Optional: Make backup copies of the main GRUB 2 directories and files. sudo cp /etc/default/grub /etc/default/grub.old. ... Remove GRUB 2. sudo apt-get purge grub-pc. ... Install GRUB 0.97. ... With grub installed, the user must still create the menu. ... Reboot.

How do I regenerate grub config?

Rebuild the grub.cfg file by running the grub2-mkconfig -o command as follows:On BIOS-based machines, issue the following command as root : ~]# grub2-mkconfig -o /boot/grub2/grub.cfg.On UEFI-based machines, issue the following command as root : ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg.

How do I manually install grub bootloader?

ResolutionMount root to /mnt. ... Mount /boot to /mnt/boot. ... Mount system pseudo file systems under /mnt. ... "change root" or chroot to /mnt. ... Under /boot/grub, there is a file called "device. ... Launch the grub interactive shell. ... In the interactive shell, you will see a "grub>" prompt. ... Type quit.More items...•

How do I use grub command line?

Booting From grub> The first line sets the partition that the root filesystem is on. The second line tells GRUB the location of the kernel you want to use. Start typing /boot/vmli , and then use tab-completion to fill in the rest. Type root=/dev/sdX to set the location of the root filesystem.

How do I remove grub from BIOS?

Originally Answered: How do I remove GNU grub and install windows boot loader? It's very simple. Just press f12 when booting screen appears, then go to BIOS. On that page at the bottom you will see an option of reset .

How do I reinstall Windows bootloader?

Automatic Windows Bootloader Repair with WinREBoot your device from the recovery disc or Windows 10/11 installation media;Click the Restore System on the installation screen;Then select Troubleshoot -> Startup Repair and select the OS whose bootloader you want to try to repair;More items...•

How do I start Windows from grub?

Add Windows to GRUB boot menuOpen a terminal and run the os-prober command with root privileges. This will search for other operating system installations besides the current distro you're booted into. ... To add these findings to the GRUB menu, execute the update-grub command with root permissions. $ sudo update-grub.

How do I use GRUB command line?

Booting From grub> The first line sets the partition that the root filesystem is on. The second line tells GRUB the location of the kernel you want to use. Start typing /boot/vmli , and then use tab-completion to fill in the rest. Type root=/dev/sdX to set the location of the root filesystem.

How do I manually install GRUB bootloader?

ResolutionMount root to /mnt. ... Mount /boot to /mnt/boot. ... Mount system pseudo file systems under /mnt. ... "change root" or chroot to /mnt. ... Under /boot/grub, there is a file called "device. ... Launch the grub interactive shell. ... In the interactive shell, you will see a "grub>" prompt. ... Type quit.More items...•

How do I boot from GRUB menu?

You can get GRUB to show the menu even if the default GRUB_HIDDEN_TIMEOUT=0 setting is in effect:If your computer uses BIOS for booting, then hold down the Shift key while GRUB is loading to get the boot menu.If your computer uses UEFI for booting, press Esc several times while GRUB is loading to get the boot menu.

How do I get out of grub menu?

To strictly answer your question, other methods have successfully worked for me, apart from ESC :exit command.normal (this caused every entry in GRUB menu to appear twice)

How to repair GRUB?

To repair Grub, you may need to know the name of the boot and root partitions where Linux is installed. If you have many partitions on your disk you may not remember which one it is. You can run fsarchiver probe simple or fsarchiver probe detailed from SystemRescuecd to show the list of filesystems of your computer.

How to re-enable grub?

The first solution is to start the Linux system which is on your hard-disk by booting from SystemRescueCd. The second solution is to boot from a rescue disk such as SystemRescueCd normally and to run the Grub installation command from a chroot environment. These two solutions are described below and they should work for both Grub1 (Grub Legacy) and Grub2.

How to find the name of a grub disk?

Once you have access to your system, you have to get a shell to run commands. You have to identify the name of the disk where Grub has to be installed. In general, it will be /dev/sda. If you have more than one disk, it may also be /dev/sdb, /dev/sdc, … You can use fsarchiver probe simple to get the list of the partitions, and then you can guess the name of the disk. Here is an example of a computer with two disks ( /dev/sda and /dev/sdb ):

Why is Grub installed at the beginning of a partition?

It can be installed at the beginning of a partition when the filesystem of that partition leaves some free space at the beginning (eg: ReiserFS does not use the first 64KB). If you move that partition, then the sectors where Grub is installed will move with it, and the bad sectors will be referenced.

Why does my Linux system complain about missing kernel modules?

This is because each specific kernel version has its own kernel modules, and the linux distribution you have installed does not provide the modules of that particular kernel. It should not be a problem since all the filesystems and disk drivers should be loaded at that stage. This is all you need to reinstall Grub.

Does grub need to be reinstalled?

If one of these sectors is overwritten then Grub will stop working. Fortunately there are solutions to recover your linux installation by reinstalling Grub, and you don’t have to reinstall Linux entirely.

Can you have multiple hard drives in GRUB?

modification of the boot priority of the hard-disks: If you have multiple hard-disks you can specify which one you want to boot from in the BIOS settings. In general Grub is installed on only one disk, so it will stop working if the BIOS tries to boot from another disk.

What to do if something goes wrong with Grub?

If anything goes wrong, you can easily fix, edit and repair the GRUB boot menu using commands . GRUB is popular among people who use dual boot setups. If you’re using a dual boot setup, you’re most probably making use of GRUB whether you’re aware or not. Sometimes, when you install Windows after installing Linux, or as it is my case, Ubuntu, ...

What is a GRUB?

GRUB or Grand Unified Bootloader is a bootloader package developed to allow users to select from two or more operating systems installed on a single disk. GRUB is what makes dual booting a PC with Windows and a Linux distribution such as Ubuntu possible. You can always install two operating systems on a disk but you’ll only be able ...

How does boot repair work?

Boot repair takes care of most of the other things that you would otherwise have to manually do via more complex commands. It also lets you copy the commands so you can simply paste them into the terminal and execute them easily.

Can a GRUB customizer break?

Be very sure of what you do with GRUB customizer though because any incompatible changes can break GRUB, in which case you will have to repair it.

Can you change the boot order of a Grub?

You can also change the boot order, so it would boot into your OS of choice by default unless you choose otherwise at the time of boot. GRUB can be edited using a tool called GRUB Customizer. To install it, just execute the following commands in a Terminal window.

Is the Grub still there?

GRUB is still there but the Windows bootloader takes preference over it, thus booting right into Windows. Today, we’ll see how to edit or repair GRUB boot menu.

How to install boot repair in Ubuntu?

To start the installation of Boot Repair in the Ubuntu live environment, open up a terminal window. To open up a terminal window in the Ubuntu live environment, press the Win key on the keyboard and search for “terminal.”. Or, press Ctrl + Alt + T on the keyboard.

What does it mean when a boot repair screen appears?

When it does start up, a loading screen will appear. This loading screen indicates that Boot Repair is scanning your computer for any traces of Grub. Please allow it to scan.

Can you repair a grub bootloader?

Note: although this guide assume s the user is repairing the Grub bootloader for Ubuntu, Boot Repair can fix almost any Linux operating system running Grub. Feel free to follow along with the guide even if you’re not an Ubuntu user!

Who shows how easy it is to repair the GRUB2 boot loader in Linux?

Jack Wallen shows you how easy it is to repair the GRUB2 boot loader in Linux.

How to see what boot repair did?

If you want to see what boot-repair did to your system, copy and paste the URL into a browser and give the report a read.

Does Grub2 work on CentOS?

Note: The tool we are going to use will work on any system that uses GRUB2. Although we'll be using a Ubuntu Desktop live instance, the process will work, even if you're repairing, say, Fe dora or CentOS. As the boot loader is GRUB2, you should be good to go--GRUB2 is the default boot loader in most Linux distributions.

Does Boot Repair have a URL?

Boot-repair has presented me with a URL so I can view the report.

Can you repair a GRUB2 boot?

Once boot-repair has completed the process, reboot your machine, remove the USB drive, and cross your fingers that the boot loader has been successfully repaired. The good news is that boot-re pair is really good at fixing the most common problems that cause GRUB2 systems to not boot. With this handy GUI tool, you won't have to bother with the more complicated command line process of repairing your Linux boot loader.

GRUB Boot Issues

The most common reason for GRUB not booting into the operating system is another OS's bootloader overwriting GRUB boot configuration. The problem occurs during an attempt a dual boot with an existing Linux installation. Another reason is the accidental removal of GRUB configuration files.

GRUB Rescue Commands

Below is the list of the commonly used GRUB Rescue commands. Use the commands in the prompts mentioned in the previous section.

Fixing Boot Failure

This tutorial covers two ways to resolve GRUB boot issues, using the GRUB Rescue prompt, and the Boot Repair tool.

How to prevent grubs in lawn?

Water grass deeply but infrequently to help prevent grubs. Image Credit: Danil Bukharov/iStock/GettyImages. Water the lawn deeply and infrequently to encourage deep root growth and a thick lawn. Grubs thrive in areas with thin grass and moist soil, so keeping the lawn as lush as possible helps prevent grubs.

What to do if grubs kill your lawn?

If grubs have killed off most of your lawn, reseeding large sections is the best option .

How to get rid of bald spots on lawn?

Sprinkle grass seeds over the area; 10 to 15 seeds per square inch is a good target quantity for a completely bald area; less will suffice if surrounding grass is still fairly healthy. Tamp the seeds down gently with your foot, then sprinkle no more than 1/4 inch topsoil over the seeds.

Why is my grass not turning green?

Grass that won't turn green, even when watered, may have root damage. Image Credit: pgaborphotos/iStock/GettyImages. Besides patches of grass turning brown and never re-greening even with plenty of water, a few telltale signs point to grubs as the cause of your lawn's failing health.

What to do if a skunk is digging in my yard?

Raccoons, skunks, or other small animals digging all over the yard for no obvious reason also could mean grubs are present. Lift up a handful of the affected grass. If it isn't loose enough to come completely free from the surrounding lawn, use a pocket knife or garden tool to cut an arc or triangular flap.

How to treat a nematode in the yard?

Apply the nematodes by spraying the areas of the most damage. Apply more nematodes to the area surrounding the problem spots, if desired. Water the yard again lightly afterwards, then every few days as needed. Feel free to treat the yard again late in fall, but before temperatures drop below freezing.

When to treat grubs in the fall?

For this reason, late summer and early autumn are ideal for treating active grubs, before they burrow deeper when temperatures drop. Beneficial nematodes, a type of microscopic worm, are the secret weapon that starts killing grubs within 48 hours after reaching them.

How to get rid of grubs in soil?

Turn over the soil with a rake or spade. Remove any grubs or grub larvae that appear when soil is turned over.

How do grubs damage lawns?

Grubs damage lawns by eating the roots of the grass. When grubs appear in your lawn, the damage can be extensive. How you repair the lawn can depend on the extent of the damage. The first step is to kill the grubs. Once this has been accomplished, use a few basic procedures to repair the lawn and prevent grubs from returning the following season.

How to keep grass seed from getting too dry?

Water the lawn again. Grass seed stays better in soil that is moist.

What insecticide kills grubs?

Ask an expert what insecticide would be appropriate for killing grub in its larvae stages. A product called Mach 2 , for instance, is considered very effective at killing white grub larvae. Apply the insecticide for at least one more year in the spring.

When is the best time to reseed a lawn?

The best time to re-seed a lawn is during the spring. Instead of seeding the lawn, you can consider laying sod. If grubs keep coming back, consult an expert to find out if a different kind of grass will be more grub resistant.

How to reinstall a broken grub?

There are a lot of methods in Linux that can be used to re-install a broken grub, some can involve the ability to work and restore the boot loader by using the Linux command line and others are fairly simple and implies booting the hardware with a Linux live CD and using the GUI indications to repair the damaged boot loader.

Can Ubuntu 16.04 rescue grub?

This procedure has been successfully tested on an Ubuntu 16.04 server edition with the Grub boot loader damaged. However, this tutorial will only cover Ubuntu server GRUB rescue procedure, although the same procedure can be successfully applied on any Ubuntu system or on the majority of Debian-based distributions.