Unable to update through available option after installing Ubuntu 12.04 LTS

Asked By 100 points N/A Posted on -


A few days ago, I installed Ubuntu 12.04 LTS (Pangoline) on my Thinkpad E420, which I had bought recently.

I downloaded the installer from the company website and really liked what I saw.

In order to get it work, there are a number of updates that have to be installed, which I have done, e.g. gimp, adobe flash player, kile and audacious. After that, I tried to update through the available update option, but I get the following popup:

Ubuntu 12.04 LTS in my think pad


Requires installation of untrusted packages

The action would require the installation of package from not authenticated



libvlc5 libvlccore5 vlv vlv-data-nox vlc-plugin-notify vlc-plugin-pulse


I am also getting stuck when I try to install the software through the software Centre (running sudo apt).

I don't want to quit Ubuntu, but I have an important assignment coming up. If I can't solve it, I will have to change it. Please help me!


Answered By 0 points N/A #151908

Unable to update through available option after installing Ubuntu 12.04 LTS


Hello Kevin Moiles,

That is an error that occurs because there are missing GPG keys for PPA’s which are required for the update manager to verify the updates, and therefore it will not be able to install the updates. Fixing that error is very simple:

  • First you will need to open a Terminal session.
  • Then you will run the following command: sudo apt-get update.
  • Next you should see the PPA’s that are not able to show up appear without a public key.
  • You will need to note them down, or just copy them from terminal and paste them in a text editor.
  • Get the right key values and replace the ones that are not working.
  • After that try running the update manager again. It should complete without any error this time round.



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