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

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .