Will microsoft Repair Tool break partitioning scheme?

Question

I am primarily a Linux user, with a dual-boot between Windows and Linux for when I need to use windows-only programs. In the middle of an update, the power went out, and now when I select Windows, it brings up a repair tool and says it is "fixing disk issues." I know that in the past many users have had issues with Windows breaking or deleting their Linux partitions, so I would like to know if this repair tool will do the same.

b550 motherboard, 5700g, 32gbddr4, 6700 xt.

Answer 1

When Windows starts its automatic repair process after an improper shutdown or power loss, it primarily focuses on fixing the Windows filesystem and boot records. By default, it targets the Windows partitions (usually NTFS) and system files. It typically does not actively scan or delete Linux partitions (ext4, Btrfs, etc.), because Windows doesn’t natively recognize those filesystems. That said, there is always a small risk if it attempts to rewrite the Master Boot Record (MBR) or UEFI boot entries. On legacy BIOS systems using MBR, Windows might overwrite the bootloader (GRUB), which can make Linux temporarily unbootable, but the partitions themselves usually remain intact. On UEFI systems, it’s less aggressive - Windows might adjust its own boot manager but generally doesn’t touch Linux partitions.

If you want to be cautious, you can avoid letting Windows fully repair itself until you have backups. Booting into a Linux live USB allows you to inspect the partition table and ensure your Linux partitions are untouched. You can do this with lsblk or sudo fdisk -l. For example:

sudo fdisk -l

These commands will list all partitions and their filesystems. If your Linux partitions appear as before (ext4, swap, etc.), Windows repair is unlikely to delete them.

If the Windows repair completes but overwrites GRUB, you can restore it from Linux with:

sudo mount /dev/sdXY /mnt   # Replace sdXY with your Linux root partition

This will restore the GRUB bootloader so both Linux and Windows are selectable again.

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hth

Marcin