我正在尝试执行更新命令sudo apt-get update，但出现错误。出了什么问题？请帮帮我。
错误：
W: mistake by getting ppa.launchpad.net/aapo-rantalainen/games/ubuntu/dists/vivid/… 404 not Found
E: Some index files failed to download. They have been ignored or old used in their place .#
答案1
这电力供应协议 ppa:aapo-rantalainen/games没有 Vivid 包。
删除 PPA：
sudo rm /etc/apt/sources.list.d/aapo-rantalainen-ubuntu-games-vivid.list
sudo apt-get update