Permission denied when accessing VirtualBox shared folder when member of the vboxsf group

Question

I'm running Ubuntu 11.04 (guest) on Windows 7 (host) with the guest additions installed. I have an auto-mount folder that maps to my D: drive on the host which I can access using sudo ls /media/sf_D_DRIVE - however, even when my user (ross) is a member of the vboxsf group I get a permission denied error when attempting to explore it. I have restarted since adding my user to the vboxsf group.

This should work because I am a member of the group (which has rwx rights), so why doesn't it?

ross@panther:~$ ls -l /media
total 8
drwxrwx--- 1 root vboxsf 8192 2011-07-03 22:24 sf_D_DRIVE

ross@panther:~$ ls -l /media/sf_D_DRIVE/
ls: cannot open directory /media/sf_D_DRIVE/: Permission denied

ross@panther:~$ id ross
uid=1000(ross) gid=1000(ross) groups=1000(ross),4(adm),20(dialout),24(cdrom),46(plugdev),112(lpadmin),120(admin),122(sambashare),1001(vboxsf)

ross@panther:~$ sudo ls -l /media/sf_D_DRIVE/
total 84
drwxrwx--- 1 root vboxsf  4096 2011-07-06 14:46 Development
# ...snip...
drwxrwx--- 1 root vboxsf     0 2011-05-25 19:13 Videos

Answer 1

Odd! I restarted after adding my user to the vboxsf group, however logging out and in again gives me access! Restarting after this and it still works. Go figure.