Ubuntu has mechanism to log user activity such as used documents. This is used to facilitate searching, but can also be intrusive to your privacy. Here is a way to disable this logging without breaking Unity or any other part of the system, execute these commands in a terminal: sudo mv /etc/xdg/autostart/zeitgeist-datahub.desktop /etc/xdg/autostart/zeitgeist-datahub.desktop-inactive rm ~/.local/share/recently-used.xbel mkdir ~/.local/share/recently-used.xbel rm -rf ~/.local/share/zeitgeist then log out and log in again.