I've just got Ubuntu 12.04.2 LTS up and running on Oracle VirtualBox as guest on a windows XP system.
When I log into Linux, often, the Update manager opens and asks me if I want to install updates which I always choose to do.
However, if I click on "install updates" it thinks for a few seconds then comes up with a NO ENTRY window and a message akin to "this would involve the installation of unverified packages" or similar. The only option is CLOSE. After clicking CLOSE, it searches for updates again and asks me if I want to install updates again and so the process becomes cyclical.
So in order to install updates I have to exit the update manager, open a terminal and enter
sudo apt-get upgrade
What's the safest way to download updates?
Can I somehow tell the update manager to "just do it"?
Or am I best to stick to using the terminal?
I'd like to stay up-to-date but in the safest way possible.
As a total n00b, I'm grateful for any advice on this.