Can't install vlc and other software : packages not coming from authenticated sources

Question

After installing Ubuntu 11.10 last week I couldn't install any mp3 or videoplayers such as vlc or any others. They show me something about a failure to install packages, and when I click on details I see this:

The action would require the installation of packages from not authenticated sources: libdvdread4 libvlc5 libvlccore4 vlc vlc-data vlc-nox vlc-plugin-notify vlc-plugin-pulse

Answer 1

You need to ensure your software sources are enabled for Restricted Extras and Multiverse.

Open the Software Centre from Unity then select Edit -> Software Sources.

In the dialogue box that opens ensure you have the following selected;

Once this is done close the box and search for VLC in the Software Centre, you will then be able to install it.

Answer 2

First and foremost, open your terminal by simultaneously pressing Ctrl+Alt+T and do the following (one line, then another):

Sudo apt-get update.
sudo apt-get upgrade.

Restart your system after finish running the above instructions.

• Click on Software Center on your launcher and type VLC on the search bar (if you couldn't find it among the items list). Click on the VLC icon and locate the Install button to install it.
• Go to your Dash Home and search for VLC. Click to test if it is working properly.

Answer 3

Just run in a terminal:

sudo apt-get install vlc

and answer Yes to the question.