While shutting down Ubuntu, following error message comes in a pop up window saying:
A program is still running:
AT SPI Registry Wrapper
Not responding.
How To Resolve AT SPI Registry Wrapper Message
To resolve this issue, where you dont need this wrapper anyways, just like I did, then simply disable it from the Ubuntu Startup Applications by following the steps below:
Goto: System -> Preferences -> Startup Applications. Find AT SPI Registry Wrapper in the Start Programs tab, and uncheck it. Close the window with Close button, and restart your system.
Your problem would have been resolved.