I executed apt update as root, but I received this error message: AppStream cache update completed, but some metadata was ignored due to errors. I have found this link that offer a solution editing this config file: /usr/share/app-info/xmls/org.freedesktop.fwupd.xml. But I have opened this and I found that I have the same code as solution.My config file

Can I update my packages with this issue? EDIT: Full log from shell:

Des:1 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB]
Obj:2 http://es.archive.ubuntu.com/ubuntu xenial InRelease  
Des:3 http://es.archive.ubuntu.com/ubuntu xenial-updates InRelease [102 kB]    
Des:4 http://security.ubuntu.com/ubuntu xenial-security/main amd64 DEP-11 Metadata [67,0 kB]
Des:5 http://es.archive.ubuntu.com/ubuntu xenial-backports InRelease [102 kB]  
Des:6 http://security.ubuntu.com/ubuntu xenial-security/main DEP-11 64x64 Icons [38,3 kB]
Des:7 http://security.ubuntu.com/ubuntu xenial-security/universe amd64 DEP-11 Metadata [19,4 kB]
Des:8 http://security.ubuntu.com/ubuntu xenial-security/universe DEP-11 64x64 Icons [25,6 kB]
Des:9 http://security.ubuntu.com/ubuntu xenial-security/multiverse amd64 DEP-11 Metadata [212 B]
Des:10 http://es.archive.ubuntu.com/ubuntu xenial-updates/main amd64 DEP-11 Metadata [293 kB]
Des:11 http://es.archive.ubuntu.com/ubuntu xenial-updates/main DEP-11 64x64 Icons [182 kB]
Des:12 http://es.archive.ubuntu.com/ubuntu xenial-updates/universe amd64 DEP-11 Metadata [119 kB]
Des:13 http://es.archive.ubuntu.com/ubuntu xenial-updates/universe DEP-11 64x64 Icons [132 kB]
Des:14 http://es.archive.ubuntu.com/ubuntu xenial-updates/multiverse amd64 DEP-11 Metadata [2.520 B]
Des:15 http://es.archive.ubuntu.com/ubuntu xenial-backports/main amd64 DEP-11 Metadata [208 B]
Des:16 http://es.archive.ubuntu.com/ubuntu xenial-backports/universe amd64 DEP-11 Metadata [212 B]
Des:17 http://es.archive.ubuntu.com/ubuntu xenial-backports/multiverse amd64 DEP-11 Metadata [212 B]
Descargados 1.186 kB en 1s (851 kB/s)                        
AppStream cache update completed, but some metadata was ignored due to errors.
Leyendo lista de paquetes... Hecho
Creando árbol de dependencias       
Leyendo la información de estado... Hecho
Todos los paquetes están actualizados.

4 Answers 4


The bug has been fixed in appstream package version 0.10.1, but the version that gets installed in Ubuntu 16.04 is 0.9.4 by default. Ubuntu 16.10 automatically receives the update as it's provided in its standard repositories.

The updated package version with the bugfix for Ubuntu 16.04 however is only provided through the xenial-backports repository, which has a lower priority than the others. This means it won't upgrade to this version unless you manually specify it.

To enable the xenial-backports repository in first place, follow How do I enable the "backports" repository? (but only enable the repository, you don't need to modify the repo priority).

After that, upgrade to the version from xenial-backports by typing:

sudo apt install appstream/xenial-backports

Now your appstream package should be upgraded to version 0.10.1.

$ appstreamcli --version
AppStream CLI tool version: 0.10.1

Now force refreshing the cache data, you should no longer see any warning:

$ sudo appstreamcli refresh --force
AppStream cache update completed successfully.
  • 6
    Hi, I am getting with last command this message: "AppStream system cache was updated, but problems were found: Metadata files have errors: /var/cache/app-info/xmls/fwupd.xml. " AppStream CLI tool version: 0.10.6
    – JIV
    Jul 11, 2018 at 14:56
  • @JIV I think you should ask a new question about that. You can include a link to this for providing context.
    – Byte Commander
    Jul 11, 2018 at 16:04
  • I am first time experiencing this issue on Ubuntu 16.04 after using it for a few years. Having the same error even though backport repository is enabled. Just post this question.
    – Sun Bear
    Jul 13, 2018 at 9:53
  • @JIV, did you post a question for "AppStream system cache was updated, but problems were found: Metadata files have errors: /var/cache/app-info/xmls/fwupd.xml. " I have the same msg as you. Have you found a solution?
    – Sun Bear
    Jul 20, 2018 at 6:13
  • I did just now - askubuntu.com/questions/1057791/…
    – JIV
    Jul 20, 2018 at 7:04

See here, fix currently in progress - https://bugs.launchpad.net/ubuntu/+source/appstream/+bug/1644498


The bugs has been fixed per 1 December, in order to get rid the bugs, you have to enable proposed repository under developer options on Software & Updates.

  • Open dash then type "Software & Updates".
  • Navigate to "Developer Options" tab.
  • Enable "Pre-release updates (xenial-proposed)" checkbox.
  • Changing repository setting required admin password, fill it on pop up.
  • Close the window then, click Reload to apply changed source (Equivalent to apt-get update).
  • Open terminal then try sudo apt-get update command.
  • Thanks Liso, but it seems the proposed fix has now been deployed (possibly within just the last hour or two), because the error just disappeared for me a few minutes ago after I did the standard apt-get update/upgrade procedure.
    – ColdCold
    Dec 6, 2016 at 9:18
  • 6
    Enabling proposed and upgrading dumbly from it can cause lots of trouble.
    – Pilot6
    Jan 12, 2017 at 11:32

Sometimes using a target release cause such problems, consider removing it if you have one. It should be in /etc/apt/apt.conf.d/<filename>, and looks something like APT::Default-Release "n=stretch,o=Debian"

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .