OSX 10.9 Mavericks VirtualBox unable to use Bridged Networking Since upgrading to OSX 10.9 Mavericks VirtualBox machines that have a Bridged Network have been unable to start.

Installing VirtualBox again solves the problem temporarily, but this does not survive a reboot (or in my case kicking the power supply cable out!).

Has anyone come up with a permanent solution for this, or at least one that does not involve a fresh install?
I've found a temporary solution.  It appears that on reboot not all the kernel extensions are loaded correctly.  However a restart of the VirtualBox startup item seems to resolve this and I can then start the machines.

sudo  /Library/StartupItems/VirtualBox/VirtualBox restart


Is the line that works for me, sometimes I have to run it twice.