After upgrading to Ibex, I found that I couldn’t sync my Palm with my Windows XP guest.
After trudging through different websites with contradictory solutions I stumbled on this, which works a charm:
Open the terminal and type
vbox /etc/group
You should end up with something like
vboxusers:x:124:john
Make a note of the group ID (124 in this case). Now run
sudo [...]