title: VirtualBox Ubuntu VM doesn't automatically sync time with host even with Guest Additions installed
body: <p>I'm running a Ubuntu VM with VirtualBox and I have both the <code>dkms</code> and <code>virtualbox-guest-additions</code> packages installed. I read in <a href="https://superuser.com/a/335873/149613">this answer</a> that the system clock should sync with the host automatically with the Guest Additions, but mine doesn't seem to be doing that. What are some possible reasons / how do I rectify this? I've tried searching for this all over but most of the hits I get off Google tell you how to <em>disable</em> the automatic time sync, not enable it. </p>
  
  <p>My host machine is running OS X 10.8, if that's of any help. </p>