The button in Software Center→Edit→Software sources... is disabled.

Is there another way to reach it or simple enable the button? What could be causing it?

If I know I can fix it myself and avoid happening again. Thanks!


I figured everything out.

For some reason, my System Settings process was called gnome-control-center. Since it seemed buggy, I removed it:

sudo apt-get remove --purge gnome-control-center

... expecting to then reinstall it to see if it would behave better.

After the uninstall I tried to access it from the top right system button and guess what... It DID show up with all the configuration buttons!

I have two guesses:

  1. The distro upgrader changed the System Settings program but didn't update the name entry for the menu, because the package was there the whole time;


  1. At some forgotten point I installed gnome packages and screwed up Ubuntu's evolution. Then the distro upgrader didn't recognize it or or opted out to leave my choice of using a gnome tool instead of, maybe, "unity control center"?

Anyway. There is the info for anyone crossing this issue. I have seen other people in the same situation around the web. I hope this helps someone.

Editor's Addition (by Anwar)

It's the installation of gnome packages and not removing them cleanly. gnome-control-center is GNOME3 sessions part and not meant to be used in Unity.

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  • 1
    It's the second one. gnome-control-center is a gnome3 part, unity-control-center is the Unity component. – Anwar Nov 2 '16 at 13:36

In Kubuntu 14.04 use Muon Discover. Just type muon discover in the search field of Kmenu or go to

**Kmenu > applications > system > software center (Muon discover) [with blue icon].

In muon discover choose the "sources" tab at the top of the window. Then click on configure software sources in the top right corner, enter your password, and enjoy!

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Is there another way to reach it ... ?

I think you can directly access it through Software & Updates either from the dashboard or from the System Settings panel (in the shutdown button).

Now for the second part of the problem:

Try reinstalling ubuntu-desktop as proposed here

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  • Thanks for your reply, Raph. Actually, I don't know if it was there before, but... – Chiur May 8 '14 at 12:39
  • Damn! After searching for over an hour. I just realized that the software sources needed to be manually reinstalled after the upgrade from 13.10. It can be installed from the Software Center. The package is called "software-properties-gtk" or "software-properties-kde", if you want to install it from the command line. Now that was really weird. I guess it is not installed by default because it is technical application and occupies 260MB in the hard drive. – Chiur May 8 '14 at 12:40
  • In my opinion, given that I upgraded from a system that had it, it should keep having it! If I was going for a fresh install, I'd like to have a check box like this: "[ ] install basic technical tools?". Or something like that, because it is actual infra-structure. It could go in the same step where you check a box for Flash. I won't bother reporting directly to Canonical, because they must have realized this confusion already. Cheers! – Chiur May 8 '14 at 12:41
  • Oh! And I had already completely removed ubuntu-desktop and and reinstalled it. It was my first trial, by the way. Wipe everything away and replace... sounds like the perfect idea :D See my replies to my own question. The problem was a bit more obscure. Thank you very much for your time and experience :) – Chiur May 8 '14 at 13:52

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