I first got this
Failed to download package files. Check internet connection
error and tried the solution that seems to work for most others who had the same problem...changing the download location. I've tried several different servers to no effect. I also tried the second solution in the link above (having apt make a new source list file).
More recently, the error has instead been "installation requires installation from unauthenticated sources." The first solution in this post is the same as the second solution from the first link from above and makes no difference in my situation. Before I start adding public keys or any other solution, I figured it would be best to post my output specifically and see what the community has to say.
Here is my output for apt-get update.
Here is my output for apt-get upgrade.
I don't have a high enough reputation to post more than two links, so here is the output for /etc/apt/sources.list directly:
~$ cat /etc/apt/sources.list
# deb cdrom:[Ubuntu 14.04.3 LTS _Trusty Tahr_ - Beta amd64 (20150805)]/ trusty main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty main restricted #Added by software-properties
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ trusty main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty universe multiverse #Added by software-properties
## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-updates universe main multiverse restricted #Added by software-properties
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty universe
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty multiverse
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse #Added by software-properties
deb http://us.archive.ubuntu.com/ubuntu/ trusty-security main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-security universe main multiverse restricted #Added by software-properties
deb http://us.archive.ubuntu.com/ubuntu/ trusty-security universe
deb http://us.archive.ubuntu.com/ubuntu/ trusty-security multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu trusty partner
# deb-src http://archive.canonical.com/ubuntu trusty partner
## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu trusty main
deb-src http://extras.ubuntu.com/ubuntu trusty main
## added myself -- http://stackoverflow.com/questions/29630434/graphviz-installation-ubuntu-14-04
deb http://security.ubuntu.com/ubuntu lucid-security main
deb http://cz.archive.ubuntu.com/ubuntu lucid main
deb http://repository.spotify.com stable non-free
# deb-src http://repository.spotify.com stable non-free
# deb-src http://repository.spotify.com stable non-free
deb http://us.archive.ubuntu.com/ubuntu/ trusty-proposed multiverse restricted universe main
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-proposed multiverse restricted universe main #Added by software-properties
Based on the 6th error from the bottom of the output for apt-get update, it seems at least one of the issues is the inability to authenticate some package from Nvidia (probably the cuda repository that I installed anyway just now -- was that terribly stupid of me to do?).
Not sure what to do next and would appreciate any guidance! Thanks in advance.
