I installed Ubuntu 14.04 LTS after a long time with Windows. Now I can't shutdown or restart Ubuntu from the GUI reliably.
I've seen some posts about grub and haven't found anything useful. But, it shuts down properly when I perform
sudo shutdown -v -h now
After that, subsequent shutdowns execute correctly from the GUI until I install a new application through the terminal.
NOTE: Windows 10 was installed first, then the Ubuntu was installed.