In VirtualBox, Ubuntu guest, Windows 7 host, I click this "Auto-mount" box, but it doesn't seem to have any effect. I have to edit fstab to get it to mount. So what is it for?

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  • what does this automount means? and why its better to have it on?
    – Amir
    Commented Jul 20, 2017 at 22:39
  • @Amir if you don't have auto-mount on then you have to manually run the mount command yourself. which is fairly cryptic for vbox shares
    – Shanteva
    Commented Jan 5, 2018 at 16:04

3 Answers 3


Make sure that the additions are installed, and that you have added your username as a member of the vboxsf group (sudo usermod -aG vboxsf <your username>).

Then you need at least to log out (or reboot) for the change to take effect.

  • You may also invoke "newgrp vboxsf" to make the addition to vboxsf effective for the current terminal.
    – ElazarR
    Commented Dec 3, 2015 at 12:29
  • 4
    Thanks, worked perfectly. Isn't this something that the installer of the guest additions should do?
    – Gigo
    Commented May 31, 2016 at 0:42

In Ubuntu this should auto-mount shared folders under /media/sf_share_name. I've had permissions issues with the auto-mounts and still use the fstab.

  • 2
    I had the same permissions issue. Then I have noticed the answer of @private_meta (below) that refers to the vboxsf group. Following his comment, all you have to do is add your user to vboxsf group: $ sudo adduser <your username> vboxsf . Then you would have access to the auto-mounts under /media/sf_share_name/ . You may have to "newgrp vboxsf" to make the addition to vboxsf group effective in your current terminal.
    – ElazarR
    Commented Dec 3, 2015 at 12:25
  • In CentOS it does absolutely nothing. Commented May 5, 2017 at 19:10

You can find information on that in the VirtualBox Manual,


Maybe your user is not in the vboxsf user group, maybe you didn't look correctly where to find it. Are you sure you installed the latest guest additions?

You can check all that, but you can refer to the manual for details if it helps.

  • 3
    There is no vboxsf group. I added it, but it didn't seem to change anything.
    – endolith
    Commented Mar 2, 2011 at 15:42
  • 1
    @endolith Have you installed the Guest Additions in your Ubuntu guest? The auto-mount (and really the shared folders feature in general) won't work without them.
    – Goyuix
    Commented Mar 2, 2011 at 16:37
  • 1
    @Goyuix: Yes, virtualbox-ose-guest-utils virtualbox-ose-guest-dkms virtualbox-ose-guest-x11 are all installed. I wouldn't be able to mount from vboxsf at all, otherwise, would I?
    – endolith
    Commented Mar 2, 2011 at 20:29

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