I have exactly the same issue : my 12.04 LTS ubuntu VM was running fine, I did the last upgrade build 15098, first it started fine so I decided to upgrade the Parallels tools too, I used the upgrade option from the terminal window after running the "sudo sh install", as usual, at the end it restarted the VM and then I can't do anything, no menu no icon nothing, I can't use the VM anymore.
After the screen saver activates in the VM it prompts me the user password, there I tried to change user and choose "ubuntu 2D" from the small menu at the right of the user name, then I type the password but same problem again.
Last edited: Jun 25, 2012