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W:Failed to fetch http://ppa.launchpad.net/plushuang-tw/uget-stable/ubuntu/dists/saucy/main/binary-i386/Packages 404 Not Found , E:Some index files failed to download. They have been ignored, or old ones used instead.

marked as duplicate by Eric Carvalho, Charles Green, Fabby, waltinator, Pablo Bianchi Apr 10 at 15:25

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run these commands in terminal,

sudo apt-get update
sudo apt-get -f install

And also check your internet connection.

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