Repair a Corrupted USB Stick with fsck.vfat

Fix FAT32 filesystem errors on flash drives and SD cards that Windows left dirty or Linux mounts read-only.

LinuxfilesystemdiskrepairusbMedium risk

Unmount the drive, then run sudo fsck.vfat -a /dev/sdb1 to automatically repair the FAT filesystem without prompts.

01Command

Command

$ sudo fsck.vfat -a /dev/sdb1

02What it does

The dosfstools package's fsck.vfat (same binary as fsck.fat) validates the two FAT tables, directory entries and cluster chains of a FAT12/16/32 filesystem. The -a flag applies the non-destructive fixes automatically, while -r asks about every repair and -v prints details — run plain fsck.vfat first if you want to see what is wrong. This resolves the common 'volume is dirty' and read-only-mount situations on flash media.

03Risk

RiskMedium risk

Requirementsdosfstools package (fsck.vfat / fsck.fat)

!Warning: Always unmount the device first and never repair the wrong device node — check with lsblk; if the stick holds irreplaceable data, copy it off with ddrescue before any repair attempt.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

fsck.fat(8) — Ubuntu man page (dosfstools)
Ubuntu manpages · community · 2026-09-17
Evidence: Man page text includes -a (automatically repair without prompts) and -v verbose mode, confirming the repair flags.
fsck.fat(8) — check and repair MS-DOS FAT filesystems
Debian manpages · community · 2026-09-17
Evidence: Page documents the -a option ('Automatically repair the file system without any prompts') and fsck.vfat as a synonym; confirms 'fsck.fat' and '-a' appear in the text.

Last verified: 2026-09-19 · Category: Files & Folders

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