Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free.

I'm trying to upgrade from 13.04 to 13.10 following this guide: http://www.unixmen.com/upgrade-ubuntu-13-04-raring-ubuntu-13-10-saucy-salamander/

user@computer:~ update-manager
Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 9: reading configurations from ~/.fonts.conf is deprecated.
Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 9: reading configurations from ~/.fonts.conf is deprecated.
gpg: /tmp/tmp82g1kk/trustdb.gpg: trustdb created
Checking for a new Ubuntu release
WARNING:root:file 'saucy.tar.gz.gpg' missing
Traceback (most recent call last):
  File "/usr/bin/do-release-upgrade", line 152, in <module>
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcherCore.py", line 278, in run
    _("Fetching the upgrade failed. There may be a network "
  File "/usr/lib/python3/dist-packages/DistUpgrade/DistUpgradeFetcher.py", line 50, in error
    return error(self.window_main.window_main, summary, message)
AttributeError: 'NoneType' object has no attribute 'window_main'
share|improve this question

2 Answers 2

I had apt-cacher installed.


Remove or edit the proxy file you added in /etc/apt/apt.conf.d/ to bypass apt-cacher.

share|improve this answer

I was getting "Failed to fetch" too. Changing the software sources in "Software & Updates" back to the "Main server" servers instead of the country specific "Server for country" let the upgrade continue.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.