In order to create a contiguous space for my file system to grow, I created a new EFI System partition at sda1 so that I can migrate it from the current partition at sda5. The move itself has been successful except for a warning which says:

kernel: FAT-fs (sda1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

I didn't notice the warning which has been there for two days when I first created the EFI partition. I unmounted the file system and performed a file system check as follows:

# umount /dev/sda1
# fsck -V /dev/sda1
fsck from util-linux 2.24
[/sbin/fsck.vfat (1) -- /boot/efi] fsck.vfat /dev/sda1 
fsck.fat 3.0.24 (2013-11-23)
0x25: Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
1) Remove dirty bit
2) No action
? 1
Leaving filesystem unchanged.
/dev/sda1: 14 files, 2435/51145 clusters

I thought removing the dirty bit would resolve this. But it didn't. What should actually be done?

1 Answer 1


This is stupid. I find myself answering my own question again. It says,

Leaving filesystem unchanged.

suggesting that nothing is changed. This actually mean that typing 1 followed by pressing enter inside the fsck prompt did not work. Anyway, the following does work:

# fsck.vfat -v -a -w /dev/sda1

The above command automatically write changes to disk. It would be great if anyone can tell me whether this is a bug in fsck or it is due to something else.

  • 5
    The man page for fsck.vfat explains that it only does a dry-run and changes nothing, unless you give either the -a or -r options. The same is true of the check tools for other filesystem types, though the specific options may vary. Feb 1, 2014 at 12:52
  • 5
    @MichaelHampton, yes indeed. The sneaky footnote says Note: If -a and -r are absent, the filesystem is only checked, but not repaired.. Those looking at man fsck would never find out :p Feb 1, 2014 at 14:13
  • 3
    @MichaelHampton, yeah, but nothing is mentioned about the dry-run. Feb 2, 2014 at 1:55
  • 1
    @MichaelHampton core fsck here (on debian 8.2) not only does not make that explicit - but also it quotes two contradictory meanings for the -r switch - just to complicate things further... Oct 30, 2015 at 22:45
  • 1
    @underscore_d Not contradictory, just confusing. One of those is a general fsck option, the other is an fs-specific option. These appear after --, and get passed through to the fs-specific tool. Oct 30, 2015 at 23:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.