Ubuntu VM - Gnome Only Shows Wallper after Upgrade

Environment
  • Ubuntu 10.10, 11.04
  • VirtualBox 4.0.6

Content
An Ubuntu virtual machine (VM) is upgraded to latest version 11.04, but only show wallpaer when logged in after installed VBoxAdditions

Went to safe mode and tried to install again. It showed
The headers for the current running kernel were not found. If the following module compilation fails then this could be the reason
However, "linux-headers-generis" was already here

Therefore, thought if GNOME had problem, OK, uninstalled and reinstalled it, but the problem was still here

Finally, found that can be simple solved by running "/opt/VBoxGuestAdditions-4.0.6/uninstall.sh"... Oops!

It can be solved by installing unity 2D if Ubuntu 11.04
$sudo apt-get install unity-2d-default-settings