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How to Fix GRUB Rescue in Windows and Linux

Geeksdigit Team

July 2, 2026

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The GRUB Rescue error is one of the most frustrating boot problems that can occur on a dual-boot or Linux-based computer. Instead of loading Windows or Linux normally, your PC stops at a grub rescue> prompt, preventing either operating system from starting. This issue usually appears after deleting a Linux partition, reinstalling Windows, changing disk partitions, or when the GRUB bootloader becomes corrupted.

GRUB (Grand Unified Bootloader) is responsible for loading Linux and, in dual-boot systems, providing a menu to choose between Linux and Windows. If GRUB cannot locate its required files or configuration, it enters rescue mode. Fortunately, in most cases, you can restore access to your operating systems without reinstalling them.

In this guide, you’ll learn several methods to fix the GRUB Rescue error in Windows and Linux.

What Causes the GRUB Rescue Error?

GRUB Rescue usually appears for one of the following reasons:

• Linux partitions were deleted.
• Windows was reinstalled after Linux.
• The GRUB bootloader is damaged.
• The boot partition was modified.
• The wrong boot drive is selected in BIOS or UEFI.
• The file system is corrupted.
• A hard drive or SSD is failing.
• A Linux update interrupted the bootloader configuration.

Understanding the cause helps determine the best recovery method.

Method 1: Check the Boot Order in BIOS or UEFI

An incorrect boot order can prevent the system from finding the proper bootloader.

1. Restart your PC.
2. Enter the BIOS or UEFI firmware by pressing the appropriate key (such as F2, Delete, Esc, or F10) during startup.
3. Open the Boot menu.
4. Verify that the correct SSD or hard drive is selected as the first boot device.
5. Save the changes and restart the computer.

If the wrong drive was selected, the system may boot normally after correcting the boot order.

Method 2: Use the GRUB Rescue Commands

If you are at the grub rescue> prompt, you may be able to boot Linux manually.

First, list the available partitions:

ls

You may see entries such as:

(hd0) (hd0,gpt1) (hd0,gpt2)

Inspect a partition:

ls (hd0,gpt2)/

Look for the /boot/grub directory.

Once you find the correct partition, set it as the root:

set root=(hd0,gpt2)

Specify the GRUB prefix:

set prefix=(hd0,gpt2)/boot/grub

Load the normal GRUB module:

insmod normal

Start the GRUB menu:

normal

If successful, you can boot Linux normally and permanently repair GRUB afterward.

Method 3: Repair GRUB Using a Linux Live USB

This is the most reliable method for restoring a damaged GRUB installation.

1. Create a bootable Linux USB.
2. Boot from the USB drive.
3. Select Try Linux instead of installing it.
4. Open a Terminal.

Identify your Linux partition:

sudo fdisk -l

Mount the Linux partition:

sudo mount /dev/sda2 /mnt

If your system uses UEFI, mount the EFI partition as well:

sudo mount /dev/sda1 /mnt/boot/efi

Bind the required system directories:

sudo mount --bind /dev /mnt/dev
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys

Enter the installed Linux system:

sudo chroot /mnt

Reinstall GRUB:

For BIOS systems:

grub-install /dev/sda

For UEFI systems:

grub-install

Update the boot configuration:

update-grub

Exit the chroot environment:

exit

Unmount the partitions and restart the computer.

Method 4: Restore the Windows Bootloader

If you removed Linux and only want to boot Windows, restoring the Windows bootloader is often the best solution.

1. Boot from a Windows 11 installation USB.
2. Select Repair your computer.
3. Open Troubleshoot.
4. Choose Advanced options.
5. Open Command Prompt.

Run the following commands one at a time:

bootrec /fixmbr

bootrec /fixboot

bootrec /scanos

bootrec /rebuildbcd

Restart your computer after the commands complete.

If successful, Windows Boot Manager will replace GRUB and boot directly into Windows.

Method 5: Use Startup Repair

Windows Startup Repair can automatically fix some boot problems.

1. Boot from the Windows installation media.
2. Select Repair your computer.
3. Choose Troubleshoot.
4. Select Startup Repair.
5. Allow Windows to diagnose and repair startup problems.

Restart the computer after the repair completes.

Method 6: Rebuild the EFI Boot Files

For UEFI systems, rebuilding the EFI boot files may resolve startup issues.

Open Command Prompt from Windows Recovery Environment.

Run:

diskpart

List available volumes:

list volume

Assign a drive letter to the EFI partition if necessary:

assign letter=S

Exit DiskPart:

exit

Rebuild the EFI boot files:

bcdboot C:\Windows /s S: /f UEFI

Restart the computer and check whether Windows boots correctly.

Method 7: Check the File System

A damaged file system can prevent GRUB from locating its configuration files.

From a Linux Live USB, run:

sudo fsck -f /dev/sda2

Replace /dev/sda2 with your Linux partition.

Allow the utility to repair any detected file system errors before rebooting.

Method 8: Check the Hard Drive

Disk problems can also trigger GRUB Rescue.

In Windows Recovery Command Prompt, run:

chkdsk C: /f /r

In Linux:

sudo smartctl -a /dev/sda

Review the SMART report for signs of hardware failure.

Method 9: Update the GRUB Configuration

If Linux boots but the GRUB menu is missing entries, rebuild its configuration.

Open Terminal and run:

sudo update-grub

The utility scans for installed operating systems and recreates the GRUB configuration file.

Method 10: Reinstall Linux

If the Linux installation is severely damaged and bootloader repair fails, reinstalling Linux may be the fastest solution.

Most Linux installers automatically reinstall GRUB during the installation process while preserving Windows in a dual-boot setup if you choose the appropriate installation option.

Be sure to back up important data before reinstalling.

How to Prevent the GRUB Rescue Error

To reduce the chances of encountering this issue again:

• Do not delete Linux partitions without restoring the Windows bootloader first.
• Keep a bootable Windows and Linux USB available for recovery.
• Back up important files regularly.
• Avoid interrupting bootloader updates.
• Verify partition changes before applying them.
• Check your storage drive periodically for errors.

These precautions can help prevent future boot problems.

Common Problems and Solutions

GRUB Still Opens After Repair

Verify that the correct boot device is selected in BIOS or UEFI and reinstall the appropriate bootloader if necessary.

Windows Doesn’t Appear in GRUB

Boot into Linux and run:

sudo update-grub

This usually detects Windows automatically and adds it to the boot menu.

“Unknown Filesystem” Error

Run a file system check using fsck from a Linux Live USB to repair any disk errors.

Bootrec /fixboot Returns “Access Is Denied”

This commonly occurs on UEFI systems. Assign a drive letter to the EFI partition and rebuild the EFI boot files using the bcdboot command.

Conclusion

The GRUB Rescue error typically occurs when the GRUB bootloader can no longer locate its configuration files or when changes to your system’s partitions disrupt the boot process. Although the error can prevent both Windows and Linux from starting, it is often recoverable without reinstalling either operating system.

Simple fixes such as correcting the BIOS boot order or manually loading GRUB may resolve the issue. For more serious problems, repairing GRUB from a Linux Live USB or restoring the Windows Boot Manager using Windows Recovery Environment are reliable solutions. If the underlying cause is disk corruption, checking and repairing the file system is also essential.

By understanding what causes the GRUB Rescue error and following the appropriate recovery method, you can restore your computer to a working state and minimize the risk of similar boot issues in the future.

Frequently Asked Questions

1. What is GRUB Rescue?

GRUB Rescue is a minimal recovery mode that appears when the GRUB bootloader cannot find its required files or configuration.

2. Will fixing GRUB delete my files?

No. Most GRUB repair methods restore the bootloader without affecting your personal data, though it’s always wise to maintain backups.

3. Can I remove GRUB and boot only Windows?

Yes. Restoring the Windows Boot Manager using the Windows Recovery Environment removes the dependency on GRUB and allows Windows to boot directly.

4. Why did GRUB Rescue appear after installing Windows?

Reinstalling Windows often replaces the existing bootloader, which can leave Linux’s GRUB configuration inaccessible until it is repaired or reinstalled.