When I go to Software & Updates and then to Other Software I get this boxes unchecked: http://repository.spotify.com stable non-free
and http://download.opensuse.org/repositories/home:/Horst3180/xUbuntu_15.10//
.
If I check them I am unable to download the updates, it will fail because of them, I guess. I tried to install Spotify so I guess that is the reason they are there. I have Ubuntu GNOME 15.10 on my machine. How to remove them from there? Thank you!
sudo apt-get update
orsudo apt-get install INSERT_PACKAGE_NAME_HERE
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