Update Manager error : Requires installation of untrusted packages

[_nedR]

When I tried to update my ubuntu yesterday, I got the following error:


Requires installation of untrusted packages

The action would require the installation of packages from not authenticated sources.

aptdaemon aptdaemon-data firefox firefox-branding firefox-globalmenu firefox-gnome-support firefox-locale-en gnome-keyring libgcr0 libgp11-0 libpam-gnome-keyring linux-generic linux-headers-2.6.38-11 linux-headers-2.6.38-11-generic linux-headers-generic linux-image-2.6.38-11-generic linux-image-generic linux-libc-dev python-aptdaemon python-aptdaemon-gtk python-aptdaemon.gtk3widgets python-aptdaemon.gtkwidgets
This error came out of the blue since Update worked fine until yesterday.

Searching online i tried the fix suggested in http://www.liberiangeek.net/2010/10/fix-requires-installation-untrusted-packages-error-ubuntu-10-10-maverick-meerkat/ which involved fetching the Public keys for 58682E70DBF506D7 and 40976EAF437D05B5. Still no luck. When i typed apt-get update i got the following error :


W: GPG error: http://archive.ubuntu.com natty-security Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://archive.ubuntu.com natty-updates Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: Failed to fetch http://deb.torproject.org/torproject.org/dists/natty/main/binary-i386/Packages 403 Forbidden
note: Please ignore the torproject error; Thats because the country i am in blocks it.

Any help is much appreciated,

_nedR

[_nedR]

Got this issue fixed thanks to Naptha's solution posted in : http://ubuntuforums.org/showthread.php?t=802156

Specifically running :


sudo rm -r /var/lib/apt/lists
sudo mkdir -p /var/lib/apt/lists/partial
sudo aptitude updateNow Update works fine.

Thanks anyway,
_nedR