I need to mount a ntfs partition and be able to use it with unix file system permissions. The problem is that, when I mount the partition using the following fstab entry, I cannot run chown and chmod successfully. It executes without error, but the file access rights are not changed.

PARTUUID=c3e3b171-d451-44e6-9f17-ffbe9e220dc7   /mnt/mounted_drive  ntfs-3g  defaults,umask=0022,uid=1000,gid=1000,errors=remount-ro,permissions 0 2

When I mount the partition without setting umask, uid, and gid I can use previously mentioned commands successfully.

PARTUUID=c3e3b171-d451-44e6-9f17-ffbe9e220dc7   /mnt/mounted_drive  ntfs-3g  defaults,errors=remount-ro,permissions 0 2

What shall I do to mount the partition properly?

  • 1
    On Unix-like operating systems such as Linux, MacOS, BSD, etc, you can run chown and chmod on ntfs filesystems but they aren't going to have any effect on the actual permissions. Does the filesystem absolutely need to be ntfs? Dec 27, 2018 at 20:05
  • I've read that the permissions option in fstab entry allows you to use permissions but without compatibility with windows, which I don't need. It seemed to work with the second mount. In the future I am planning to reformat the partition to ext4, but currently don't have free space to backup the data.
    – icepopo
    Dec 28, 2018 at 8:04
  • The permissions option just allows permissions and rights to be set with individual files and options inside which is default. The command will work on an ntfs filesystem but it will have no effect. Dec 28, 2018 at 20:28

1 Answer 1


With NTFS-3G, setting the owning user and group seems only to be possible when a UserMapping file containing a mapping for the targeted user/group is present. This is not really clear from the documentation, but I'm testing it just now and that is what is happening.

If compatibility with an existing Windows installation is not needed, create an empty file .NTFS-3G/UserMapping on the mounted partition and fill it via:

getRUI4() { od -An -N4 -tu4 /dev/random | tr -d ' '; }
echo ":users:S-1-5-21-$(getRUI4)-$(getRUI4)-$(getRUI4)-513" | sudo tee -a $USERMAPPING >/dev/null
echo "$(id -un):$(id -gn):S-1-5-21-$(getRUI4)-$(getRUI4)-$(getRUI4)-1001" | sudo tee -a $USERMAPPING >/dev/null

If you want to use existing Windows SIDs, you can instead use the program ntfsusermap on an unmounted (!) partition, which will interactively ask you to specify user- and group-names (do not need to be numeric, regardless of the message) for given paths where it first finds an as of yet unmapped ID. This is quick to do.

User and group root is mapped by default, as is other. The above lines will create a mapping for users group, and the current user. Repeat as necessary.

Also, in my case, I mount the drive with the options


However, in your case you should not need any of them, although I find that these options improve upon the default, as otherwise for instance chown/chmod fail silently in case of errors.

  • 1
    Perhaps you could add a reference link such as: tuxera.com/community/ntfs-3g-advanced/ownership-and-permissions/… ?
    – A.B
    Jan 4, 2019 at 15:02
  • That is a nice page, and I'll also recheck whether the comment "the last number in the SID must be greater than the equivalent number for any explicitly mapped user" makes my "all must be explicit" issue goes away. This would more or less make my whole answer obsolete ^_^
    – gimpf
    Jan 4, 2019 at 16:52
  • Before reading your answer I didn't know it was possible heh. Then I looked at tuxera.
    – A.B
    Jan 4, 2019 at 16:54

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