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I've been experimenting with Ubuntu 10.04(64bit) inside a VirtualBox VM. This isn't my first experience with Linux, but I'm still very much a Linux noob.

Whenever I try to install software from the Ubuntu Software Center, the installation gets interrupted and I get a warning that this installation requires untrusted sources. I can install anything I want using apt-get, it's just the gui that doesn't work. I've done research on the issue and taken the following precautions with no result:

under software sources

  • Allowed Canonical partners
  • Allowed source code
  • Changed the download source to main server

I get no errors when running an apt-get update. Can anyone shed some light on the issue?

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Ubuntu likes to forget some of the package signing keys it needs. To fix it, run the following commands on a terminal:

gpg --keyserver --recv-keys 40976EAF437D05B5
apt-key add ~/.gnupg/pubring.gpg
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The first command times out, and thus the second line didn't work. Is there another key server? – Casbar Feb 25 '11 at 19:34
Try – farfromhome Feb 26 '11 at 2:07
Sorry it took so long to reply. I've been neck deep in work. Anyway I tried the using the same command that Patches suggested, but with substituted in for like farfromhome suggested, but no dice. The terminal reports back that the key is unchanged. I still can't use the software center. – Casbar Mar 8 '11 at 16:18
@Casbar: as a workaround for the moment you are still able to use the Synaptic Package Manager GUI, available in the Administration > System menu. It'll prompt you when you have a key problem rather than denying the operation. It's a little more advanced than the Software Center, but still probably a lot easier than using apt-get. – Patches Mar 8 '11 at 22:31
That's what I've been doing. I was just hoping that I get the Software Center to work. – Casbar Mar 20 '11 at 5:30

Are you trusting restricted extras/third party sources? Are canonical-partners and source code the only things you are trusting? On an install that i was using the 3rd party stuff, i was trusting like 4 different repositories.

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I forgot to mention that. I also allowed using 3rd party stuff. – Casbar Feb 25 '11 at 19:21
@Casbar: in that case you probably missing your a key for one of your third-party APT repositories. If you post the contents of your /etc/apt/sources.list, the contents of all the files in /etc/apt/sources.list.d/, and the output from sudo apt-key list we might be able to identify what key is missing. – Patches Mar 8 '11 at 22:29

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