How To Fix Arch Linux After Windows Breaks It

2026/04/16

If you dual boot Windows and Linux, especially if your Windows installation uses BitLocker, you may run into situations where Windows renders your Linux installation unbootable. If you are in a situation where you may need to boot into Windows every once in a while, this guide will show you how to fix your Linux installation after Windows inevitably breaks it.

This guide is mainly for Arch Linux but will likely work with other Linux distros as well with some modifications, but I recommend using the Arch ISO to repair your installation. You should have moderate Linux knowledge before using this guide. Read the guide in its entirety before following it.

Notes

Set Up

Reformat Boot Partition

If you are using Arch, feel free to simply wipe your /boot partition without backing it up, as long as you are only storing bootloader and kernel stuff in that partition. Replace /dev/sda1 with your boot partition’s device path.

mkfs.fat -F32 /dev/sda1 # Reformat /boot partition

Mount partitions

mount /dev/sda2 /mnt # Root partition
mount /dev/sda1 /mnt/boot # Boot partition
mount /dev/sda3 /mnt/home # Home partition

Make sure you mount all partitions used by your Linux installation, as we will need the entire filesystem set up for the fstab.

Reinstall GRUB and Linux

# Generate fstab
genfstab -U /mnt > /mnt/etc/fstab

# chroot into existing installation
arch-chroot /mnt

# Reinstall GRUB, again replace /dev/sda with your boot partition's
# device path, not partition path (e.g. NOT /dev/sda1)
grub-install --target=x86_64-efi --efi-directory=/boot /dev/sda

# Reinstall linux (and/or linux-lts), most likely no need for internet since it's
# probably cached in /var/cache/pacman
pacman -S linux linux-lts

# Remake GRUB config
grub-mkconfig -o /boot/grub/grub.cfg

# Clean up
exit
umount -R /mnt
reboot

Unplug the USB and you should be all set! You may need to fix the boot order in your BIOS but your Arch installation should be bootable now.

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