How to repair a corrupted FAT32 file system

Try typing the following command in the Linux terminal:

sudo dosfsck -w -r -l -a -v -t /dev/sdc1

sdc1 is usually your pen drive. You can find your pen drive by typing mount in terminal. It's somewhere inside. If that command takes too much time for you, avoid -t switch.

• -w means write to disk immediately.
• -r means to do disk check interactively (ask you what to do to when encountering errors). On newer versions of dosfsck this is the default.
• -l means to list the filenames processed.
• -a means automatically fix errors. Do not use it, if You want to have more control over fixing possible errors.
• -v means verbose mode. Generates slightly more output.
• -t means mark unreadable clusters as bad.

If you want to be sure not to lose your data, create a backup of the source device first.

You can try Dosfsck, which is a component of dosfstools.

For this, type in terminal:

sudo apt-get install dosfstools

To use Dosfsck, you have to indicate the device address you want (Ex. /dev/sdb1, /dev/sdb2, or other device.).

To know your device address, open the terminal (CTRL+ALT+T), then run this command:

mount

If your partition is /dev/sdb1, for example, then unmount it first by running this command:

sudo umount /dev/sdb1

Now you can verify and repair your partition by running this command:

sudo dosfsck -t -a -w /dev/sdb1

Hope this helps.

Note:

if you receive the following error, when your USB flash drive is not recognized:

Error: Buffer I/O error on device sdb1

Run this command:

dmesg|tail

If the output is:

end_request: I/O error, dev sdb1, sector 0
Buffer I/O error on device sdb1, logical block 0

Run this command:

sudo dosfsck -t -a /dev/sdb1

Of course, you must change the device address to your needs, like i wrote above.

dosfsck cheatsheet

These examples will use FAT32 and /dev/sdc1

fsck.vfat -n /dev/sdc1 - a simple non-interactive read-only check

fsck.vfat -a /dev/sdc1 - checks the file system and fixes non-interactively. Least destructive approach is always used.

fsck.vfat -r /dev/sdc1 - interactive repair. User is always prompted when there is more than a single approach to fixing a problem.

fsck.vfat -l -v -a -t /dev/sdc1 - a very verbose way of checking and repairing the filesystem non-interactively. The -t parameter will mark unreadable clusters as bad, thus making them unavailable to newly created files and directories.

Also try:

fsck.vfat -r /dev/sdXn