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I am trying to update Ubuntu 12.04 using the Update Manager, but when I click the Check button in the Update Manager window I get an error saying:
Failed to download repository information
In the details it shows:
W:Failed to fetch http://ppa.launchpad.net/ronmi/wallbox/ubuntu/dists/precise/main/source/Sources 404 Not Found W:Failed to fetch http://ppa.launchpad.net/ronmi/wallbox/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found E:Some index files failed to download. They have been ignored, or old ones used instead.
Normal updates that show up automatically work just fine, but I want to upgrade my Ubuntu to the newer version without removing it and installing the new one. What do I have to do to get this update to download and install?