root@ubuntu:~# mount -t vboxsf xyzzy /media/xyzzy mount: wrong fs type, bad option, bad superblock on xyzzy, missing codepage or helper program, or other error (for several filesystems (e.g. nfs, cifs) you might need a /sbin/mount.Making the shared folder automount and reboot works, but I want to mount it to a specific path. Reinstalling GuestAddition doesn't help. It turns out that it's an old problem resurfacing. The root cause is that /sbin/mount.vboxsf is an invalid symlink. The fix is this:
helper program) In some cases useful info is found in syslog - try dmesg | tail or so root@ubuntu:~# dmesg | tail ... [ 1292.150065] sf_read_super_aux err=-22 root@ubuntu:~# mount -t vboxsf -o gid=1000,uid=1000 xyzzy /media/xyzzy mount: Protocol error root@ubuntu:~# dmesg | tail ... [ 1348.460432] sf_read_super_aux err=-71
root@ubuntu:~# updatedb # first make sure locate is up to date. root@ubuntu:~# locate mount.vboxsf # find the real location. /opt/VBoxGuestAdditions-4.3.10/lib/VBoxGuestAdditions/mount.vboxsf /sbin/mount.vboxsf # this is the bad symlink. root@ubuntu:~# ln -sf /opt/VBoxGuestAdditions-4.3.10/lib/VBoxGuestAdditions/mount.vboxsf /sbin/mount.vboxsfNow I can mount.
If I want to add the mount point to /etc/fstab so that it gets mounted at boot time, the problem is that vboxsf is not loaded automatically early in the boot, so again it fails to mount. The solution is to add vboxsf to /etc/modules.
root@ubuntu:~# echo vboxsf >> /etc/modulesNow when I reboot, the shared folder is mounted correctly at boot time.