Solution:
Root Cause: Partition Table Offset or Drive Designation Shift
During major updates (such as feature updates or disk partition re-alignments), Windows Update frequently resizes or recreates the Windows Recovery Environment (WinRE) partition or modifies the GUID Partition Table (GPT) header. This alters the numerical index or UUID of adjacent Linux root (
/) or
/boot partitions. When stage 1 of GRUB (embedded in the EFI System Partition or MBR) attempts to load stage 2 modules from the path stored in its
$prefix environment variable (e.g.,
(hd0,gpt5)/boot/grub), the partition target points to a non-existent offset, causing stage 1 to drop into the
grub rescue> environment.
Diagnostic Verification:
At the grub rescue> prompt, list all detected storage devices and partitions:bash
ls
Query each partition sequentially to find the Linux filesystem containing the GRUB directory:bash
ls (hd0,gpt1)/
ls (hd0,gpt2)/
Look for the partition that returns ext2, ext4, or lists /boot and /etc instead of returning error: unknown filesystem.Step-by-Step Fix:
1.Manually Load GRUB Core Modules from Rescue Shell:
Set the root partition and prefix variable to the correct Linux partition identified above (e.g., (hd0,gpt5)): bash
set root=(hd0,gpt5)
set prefix=(hd0,gpt5)/boot/grub
Load the normal execution module and transition to the standard GRUB shell: bash
insmod normal
normal
2.Boot into the Installed Linux Environment:
Highlight your primary Linux entry from the standard GRUB menu, press e to edit commands, and verify the root=UUID=... string matches the partition.Press Ctrl + X or F10 to boot into Linux.3.Reinstall GRUB Stage 2 and Rebuild Configuration in Linux:
Once booted into your Linux desktop/terminal, open a shell and reinstall GRUB to write correct partition pointers to the EFI System Partition (ESP): bash
sudo grub-install /dev/nvme0n1
*(Replace
/dev/nvme0n1 or
/dev/sda with your system disk name).*
Update the grub.cfg file to scan and regenerate device maps: bash
sudo update-grub
4.Fix via Live USB Chroot Method (If Manual Module Loading Fails):
If insmod normal fails with file-not-found errors, boot into a Linux Live USB.Open a terminal and mount your system root, EFI, and system pseudo-filesystems: bash
sudo mount /dev/nvme0n1p5 /mnt
sudo mount /dev/nvme0n1p1 /mnt/boot/efi
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
Enter the chroot environment and reinstall GRUB: bash
sudo chroot /mnt
grub-install /dev/nvme0n1
update-grub
exit
Prevention & Long-Term Monitoring:
Ensure /etc/fstab references partitions by immutable UUID (UUID=xxxx) rather than block device names (/dev/sdaX).