Hace algunos días que aparece un molesto error en mi Ubuntu, relacionado con las actualizaciones del sistema. El error que aparece es:
Reading package lists… Done
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com oneiric Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>W: GPG error: http://archive.canonical.com oneiric Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://archive.canonical.com lucid Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/oneiric/Release
W: A error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://extras.ubuntu.com oneiric Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>W: GPG error: http://archive.canonical.com oneiric Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: GPG error: http://archive.canonical.com lucid Release: The following signatures were invalid: BADSIG 40976EAF437D05B5 Ubuntu Archive Automatic Signing Key <ftpmaster@ubuntu.com>
W: Failed to fetch http://extras.ubuntu.com/ubuntu/dists/oneiric/Release
W: Some index files failed to download. They have been ignored, or old ones used instead.
Este error viene acompañado del icono 
permanente en la barra superior. He encontrado en ubuntuforums la manera de solucionarlo. Allá va:
pedro@pedro-laptop:~$ sudo su
[sudo] password for pedro:
root@pedro-laptop:/home/pedro# cd /var/lib/apt
root@pedro-laptop:/var/lib/apt# mv lists lists.old
root@pedro-laptop:/var/lib/apt# mkdir -p lists/partial
root@pedro-laptop:/var/lib/apt# apt-get clean && apt-get update
[sudo] password for pedro:
root@pedro-laptop:/home/pedro# cd /var/lib/apt
root@pedro-laptop:/var/lib/apt# mv lists lists.old
root@pedro-laptop:/var/lib/apt# mkdir -p lists/partial
root@pedro-laptop:/var/lib/apt# apt-get clean && apt-get update
Listo!! 😀