How to Rescue a Broken CentOS Filesystem and Fix Windows Boot Issues

CentOS Filesystem Repair

1. Mount ISO and enter rescue mode

Mount the CentOS installation ISO to the VM/CD‑ROM or insert a boot disk.

Reboot the system and boot from the ISO.

In the boot menu choose Troubleshooting → Rescue a CentOS system .

2. Enter rescue environment

After boot the system presents a text interface with options: Continue: try to mount the existing system and enter a chroot environment. Read-Only: mount the filesystem read‑only. Skip: do not mount, enter a minimal rescue environment.

If you only need to repair the filesystem, choose Skip .

3. Scan and activate LVM volumes

In rescue mode, selecting Skip prevents automatic LVM activation, so devices such as /dev/mapper/centos-root are invisible. To repair XFS you must manually activate LVM.

lvm vgscan
lvm vgchange -ay

After activation you can see /dev/mapper/centos-root, centos-home, etc.

4. Execute xfs_repair

The partition is not mounted, so you can run: xfs_repair /dev/mapper/centos-root If errors persist, try the force option: xfs_repair -L /dev/mapper/centos-root ⚠️ Note: -L discards the XFS log, which may lose recent unwritten data, but usually restores system usability.

For ext4 systems use fsck -y on the logical volume.

6. Reboot after repair

reboot

Windows Boot Repair

Windows Server 2022 VM stuck on the Windows logo.

Attempted boot repair with a third‑party ISO (wepe) – unsuccessful.

Boot from an official Windows 2022 ISO, click Repair your computer → Troubleshoot → Advanced options → Command Prompt .

Identify the system drive inside the recovery environment; the virtual machine shows only ISO drives, so the actual system disk (virtio) is not visible.

Load the virtio driver:

drvload E:\virtio-win\viostor\2k22\amd64\viostor.inf

Replace E: with the drive letter where the virtio ISO is mounted.

After driver load, run diskpart to list disks and volumes.

diskpart
list disk
list volume
exit

The boot partition is C:, the system partition is F:.

Use bootrec and bcdboot to repair the bootloader and rebuild the BCD:

bootsect /nt60 C: /mbr

nt60 writes the boot sector format used by Windows Vista/7/8/10/11/Server 2008+. /mbr rewrites the Master Boot Record, suitable for legacy BIOS boot. C: is the boot partition.

Recreate boot files from the system directory:

bcdboot F:\Windows /s C: /f BIOS

F:\Windows is your Windows system folder. /s C: specifies the boot partition (the “System Reserved” partition). /f BIOS indicates a legacy BIOS boot (not UEFI).

Change the boot order to hard‑disk and reboot. After the MBR fix the VM may show a blue‑screen loop, then press F8 to enter Safe Mode, which auto‑repairs; reboot again to boot normally.