I am not able to update apps or the OS. While upgrading from the terminal, I am getting this error message:

Do you want to continue? [Y/n] y 

(Reading database ... 271161 files and directories currently installed.)
Preparing to unpack .../appstream-data-pantheon_0.3.0-0~14~ubuntu0.4.1_all.deb ...

Unpacking appstream-data-pantheon (0.3.0-0~14~ubuntu0.4.1) ...

dpkg: error processing archive /var/cache/apt/archives/appstream-data-pantheon_0.3.0-0~14~ubuntu0.4.1_all.deb (--unpack):

 trying to overwrite '/usr/share/app-info/yaml/pantheon_xenial-main_amd64.yml.gz', which is also in package appstream-data-pantheon-loki-stable 0.4+r13~ubuntu0.4.1

Processing triggers for appstream (0.10.6-1~ubuntu16.04.2) ...

AppStream cache update completed successfully.

Errors were encountered while processing:

E: Sub-process /usr/bin/dpkg returned an error code (1)

3 Answers 3


To solve the problem "public key is not available: NO_PUBKEY A74F73EFFE70B91C", import the key:

wget -q "http://packages.elementary.io/key.asc" -O- | sudo apt-key add -

Following what I've found about these topics, I think you either need to remove the conflicting package, or you need to overwrite it explicitly (I have no idea why its not an option that pops up while you are trying to install):

sudo dpkg -i --force-overwrite /var/cache/apt/archives/appstream-data-pantheon_0.3.0-0~14~ubuntu0.4.1_all.deb


  • Hi @Mike Rodov. Thanks for this one. I did that now. But now I am facing with error like this: <b>W: GPG error: packages.elementary.io/appcenter xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY A74F73EFFE70B91C W: The repository 'packages.elementary.io/appcenter xenial InRelease' is not signed. N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use. N: See apt-secure(8) manpage for repository creation and user configuration details. </b>
    – Abhay Bh
    Commented May 25, 2017 at 8:30
  • try this askubuntu.com/questions/20725/…
    – Mike Rodov
    Commented May 25, 2017 at 8:41

This will be a late reply, but here's how I fixed this problem:

  • Removed the problematic URL lists from the /etc/apt/sources.list file
  • Rebooted the machine
  • Re-added the URL lists back to the /etc/apt/sources.list file with appropriate URLs

This helped me download latest updates from elementary software, and is how I fixed the problem.

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