"This requires installing packages from unauthenticated sources" warning not useful

[Alan Pope 🍺🐧🐱 🦄]

My machine was previously 12.10 and I updated to raring. On 12.10 I had Variety (wallpaper changer) installed. I wanted to run latest Variety on my raring machine. Unfortunately they haven't built a package for raring so I did what many people do, and use the quantal package. I did this by manually adding the "deb http://... " line to my sources. I can't use add-apt-repository in this case because that will try to add a "raring" line to my sources.

I opened update manager to update and it found the latest variety and offered me the option of installing it. I clicked the install button and after a bit of work it popped up a dialog "This requires installing packages from unauthenticated sources" with only the option of "Ok" and "Settings" available.

Note that if I'd done an update via "apt-get upgrade" on the command line it would issue a "WARNING" that this was untrusted, but would still allow me to update it. So the message in update manager is somewhat unhelpful as it doesn't tell me how I can fix the issue to get the package I want to be installed.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: update-manager 1:0.181
ProcVersionSignature: Ubuntu 3.8.0-5.10-generic 3.8.0-rc6
Uname: Linux 3.8.0-5-generic x86_64
ApportVersion: 2.8-0ubuntu4
Architecture: amd64
Date: Fri Feb 8 09:56:49 2013
EcryptfsInUse: Yes
GsettingsChanges:
 b'com.ubuntu.update-manager' b'first-run' b'false'
 b'com.ubuntu.update-manager' b'launch-time' b'1360316531'
 b'com.ubuntu.update-manager' b'show-details' b'true'
 b'com.ubuntu.update-manager' b'window-height' b'506'
 b'com.ubuntu.update-manager' b'window-width' b'784'
InstallationDate: Installed on 2012-01-02 (402 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120102)
MarkForUpload: True
PackageArchitecture: all
SourcePackage: update-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[viengxay (dong-2499)]

<email address hidden>

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Matthew Paul Thomas (mpt)]

This problem can be caused by a messed-up file in /var/lib/apt/lists/. The problem can be fixed by deleting all files in that directory, then doing an apt-get update to regenerate them. So the error alert should contain a button to try that for you.