When you install Ubuntu 13.10 and then update, the black screen shows but the tool bar still shows.
First, shut down the VM, then select it but do not open. Go to Parallels >VM>Configure>Hardware>Video and "Un-Check" 3D acceleration box. Then open 13.10 and now you will see the Entire screen black. Shut 13.10 down and once again go to Parallels>VM>Configure>Hardware>Video and Re-Enable 3D acceleration (Check the box). Open up 13.10 and everything will be back to normal and you'll see all the apps were updated as well.
Thanks! This proved very helpful.