This may be related to bug #872472 ("Xubuntu Oneiric does not display "remove cd and hit Enter to continue" when installing from desktop cd"). The code area where the shutdown hangs in that bug appears to be the same as that identified by Colin Watson in comment #6 of this bug. The problem is also intermittent suggesting a race condition.
This may be related to bug #872472 ("Xubuntu Oneiric does not display "remove cd and hit Enter to continue" when installing from desktop cd"). The code area where the shutdown hangs in that bug appears to be the same as that identified by Colin Watson in comment #6 of this bug. The problem is also intermittent suggesting a race condition.