after I upgraded Ubuntu Gnome 15.10 (Wily Werewolf) to 16.04 (Xenial Xerus), I cannot start synaptic or aptitude for installing new software, and 'apt-get install whatever' does not work either. Here is the error I always get:

The value 'wily is invalid for APT::Default-Release as such a release is not available in the sources.

I read a lot about this error on Google etc., but the solutions proprosed on the web only work for older versions of Ubuntu or Debian. What I tried e.g. was checking the value of APT::Default-Release within /etc/apt/apt.conf, but it is not set there, it is not set in any text file within /etc/apt/ or any of its subdirectories. I removed all files from the directory /etc/apt/sources.list.d, because these were related to older Ubuntu versions.

Anymore ideas?

P.S. 1: A bit more information about my environment:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04 LTS
Release:    16.04
Codename:   xenial

P.S. 2: Output from sudo apt edit-sources (removed commented lines):

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial main restricted
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial main restricted

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates main restricted
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates main restricted

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial universe
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial universe
deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates universe
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates universe

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial multiverse
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial multiverse
deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates multiverse
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-updates multiverse

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-backports main restricted universe multiverse

deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security main restricted
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security main restricted
deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security universe
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security universe
deb http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security multiverse
deb-src http://ubuntu.mirror.lrz.de/ubuntu/ xenial-security multiverse

deb http://archive.canonical.com/ubuntu xenial partner
deb-src http://archive.canonical.com/ubuntu xenial partner

deb http://archive.canonical.com/ xenial partner
  • 1
    Please check your version using 'lsb_release -a' and add the output to the above post. In addition run 'sudo apt edit-sources' (opens your sources in default editor) and paste the output as well. For me it sounds like your apt sources do refer to wily sources instead of xenial
    – dufte
    May 11, 2016 at 7:29
  • 1
    I would try to move '/root/.synaptic/synaptic.conf' to '/root/.synaptic/synaptic.conf.backup' and see if that helps. Assuming there are errors in synaptic.conf. If it doesnt helps - revert the change.
    – dufte
    May 11, 2016 at 7:52
  • Did that too, but still doesn't work :-/. May 13, 2016 at 7:12
  • Just 'sudo apt clean'?
    – emk2203
    May 13, 2016 at 13:09
  • Which server you are using to download programs? "System Settings" -> "Download from" section? Maybe selecting it to main server can be good.
    – al0s
    May 13, 2016 at 13:28

3 Answers 3


Open /etc/apt/apt.conf.d/01ubuntu using nano, like

sudo nano /etc/apt/apt.conf.d/01ubuntu

Then , type the following as it is:

APT::Default-Release "xenial";

Clean your apt cache by running:

sudo rm -rfv /var/lib/apt/lists/*

Then create the the partial folder which was removed by the previous command:

sudo mkdir -pv /var/lib/apt/lists/partial

To make sure, that you have cleaned your lists, run the following command:

sudo apt clean && sudo apt autoclean

Now, update your repository information:

sudo apt update --fix-missing

This should fix your errors.

  • Well, your answer looks quite elaborated, but the other guy's been first, sorry. May 14, 2016 at 20:45
  • I did upgrade from 15.10 to 16.04 but I can't find /etc/apt/apt.conf.d/01ubuntu on my machine. should I create it ?
    – Cristiano
    Jul 26, 2016 at 18:40
  • @Cristiano Yes, you can manually create the file. Apt will automatically load the settings of the file. Jul 26, 2016 at 18:42
  • thanks @AbhimanyuSaharan, but unfortunately I'm still getting the annoying message:"The value 'trusty-proposed' is invalid for APT::Default-Release...". Do you know where this value is set ? I'm running xenial.
    – Cristiano
    Jul 26, 2016 at 19:55
  • @Cristiano Try running grep command to search for the file. grep trusty-proposed /etc/apt/* I have not tested this command but see if it helps you Jul 27, 2016 at 3:37

If you have problems with a "stuck" apt or the higher-level programs aptitude or synaptic, a cleaning of the apt cache may be necessary.

This is especially the case after a distribution update.

sudo apt clean

is quick and easy and helps with a lot of stuck apt systems. I do it routinely after a lot of updates have been made, or after a dist-upgrade.


that mirror was broken untill earlier this morning , see the date and time on the Xenial folders. It should work now.


Its best to use the standard redirector for your country instead as it would not have included a broken mirror.


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