this failure is at boot with systemd warnings then a complete hang.
remove the fstab entry in the guest and the guest starts fine and the share folder can be mounted without incident…and yes the fstab entry is proper and works perfectly in other guest machines i.e. two other opensuse 12.3 guests, both having vitrualbox guest tools 4.2.18.
some investigation at virtualbox.org suggests that there is a problem with the 3.11 kernel and versions previous to 4.2.22 but the way i read the bugreports the shared folders won’t mount manually either which is not the case with me.
i am handcuffed to 4.2 for the time being and need a workaround, hopefully someone has had the same problem and can advise…
thanks in advance