Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

When I run update manager I always get this message "The action would require the installation of packages from not authenticated sources." details "libv4l-0 libv4lconvert0"

I also can not get the software center to install anything. I get an error message telling me to check my internet connection but I am connected to the internet, shortly after I get an error message just like the one I get from update manager. How do I fix this?

share|improve this question
Do you get E: or W: errors with the result? If so could you post them here please – Ringtail Feb 14 '12 at 19:02
This can probably be fixed by Same symptoms – Jjed Mar 16 '12 at 5:44
possible duplicate of What is the easiest way to resolve apt-get BADSIG GPG errors? – Jjed Mar 16 '12 at 5:48

Here is one method to allow for installing untrusted 3rd party software.

From a command line, run sudo apt-get update

At the end of the command output, you will see an error similar to the following message:

W: GPG error: precise Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 6AF0E1940624A220

Copy the alpha-numeric string following the NO_PUBKEY message. In this case, it will be 6AF0E1940624A220

Next, enter the following command, using the alpha-numeric string copied from the above-mentioned error message:

sudo apt-key adv --keyserver --recv-keys 6AF0E1940624A220

This will load the applications public key into your list of 'trusted' sources.

After running this command, you should be able to install updates from the software center.

share|improve this answer

You could open your software sources and in the box marked "source code" put a check there.

share|improve this answer

To bypass the message, you can try to update and upgrade from the command line. It does not raise the same issues.

sudo apt-get update
sudo apt-get upgrade

This shall do the trick.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.