apt-get update 404错误，没有任何PPA
当运行sudo apt-get update时，我得到404错误，我没有任何PPA。
jeggy@Jeggy-XPS:~$ sudo apt-get update [sudo] password for jeggy: Ign http://dk.archive.ubuntu.com utopic InRelease Ign http://dk.archive.ubuntu.com utopic-updates InRelease Ign http://dk.archive.ubuntu.com utopic-backports InRelease Hit http://dk.archive.ubuntu.com utopic Release.gpg Hit http://dk.archive.ubuntu.com utopic-updates Release.gpg Hit http://dk.archive.ubuntu.com utopic-backports Release.gpg Hit http://dk.archive.ubuntu.com utopic Release Hit http://dk.archive.ubuntu.com utopic-updates Release Ign http://extras.ubuntu.com utopic InRelease Hit http://dk.archive.ubuntu.com utopic-backports Release Hit http://extras.ubuntu.com utopic Release.gpg Hit http://extras.ubuntu.com utopic Release Ign http://security.ubuntu.com utopic-security InRelease Get:1 http://security.ubuntu.com utopic-security Release.gpg [933 B] Hit http://extras.ubuntu.com utopic/main Sources Get:2 http://dk.archive.ubuntu.com utopic/main Sources [1.046 kB] Get:3 http://security.ubuntu.com utopic-security Release [59,7 kB] Hit http://extras.ubuntu.com utopic/main amd64 Packages Hit http://extras.ubuntu.com utopic/main i386 Packages Get:4 http://security.ubuntu.com utopic-security/main Sources [7.232 B] Get:5 http://security.ubuntu.com utopic-security/restricted Sources [14 B] Get:6 http://security.ubuntu.com utopic-security/universe Sources [14 B] Get:7 http://security.ubuntu.com utopic-security/multiverse Sources [14 B] Get:8 http://security.ubuntu.com utopic-security/main amd64 Packages [15,0 kB] Get:9 http://security.ubuntu.com utopic-security/restricted amd64 Packages [14 B] Ign http://extras.ubuntu.com utopic/main Translation-en_US Get:10 http://security.ubuntu.com utopic-security/universe amd64 Packages [2.645 B] Ign http://extras.ubuntu.com utopic/main Translation-en Get:11 http://security.ubuntu.com utopic-security/multiverse amd64 Packages [14 B] Get:12 http://security.ubuntu.com utopic-security/main i386 Packages [14,6 kB] Get:13 http://security.ubuntu.com utopic-security/restricted i386 Packages [14 B] Get:14 http://security.ubuntu.com utopic-security/universe i386 Packages [2.652 B] Get:15 http://security.ubuntu.com utopic-security/multiverse i386 Packages [14 B] Hit http://security.ubuntu.com utopic-security/multiverse Translation-en Hit http://security.ubuntu.com utopic-security/restricted Translation-en Hit http://security.ubuntu.com utopic-security/main Translation-en Hit http://security.ubuntu.com utopic-security/universe Translation-en Get:16 http://dk.archive.ubuntu.com utopic/multiverse Sources [171 kB] Get:17 http://dk.archive.ubuntu.com utopic/multiverse amd64 Packages [131 kB] Get:18 http://dk.archive.ubuntu.com utopic-updates/main Sources [4.264 kB] Get:19 http://dk.archive.ubuntu.com utopic-updates/restricted Sources [7.232 B] Get:20 http://dk.archive.ubuntu.com utopic-updates/universe Sources [14 B] Get:21 http://dk.archive.ubuntu.com utopic-updates/multiverse Sources [14 B] Get:22 http://dk.archive.ubuntu.com utopic-updates/main amd64 Packages [14 B] Get:23 http://dk.archive.ubuntu.com utopic-updates/restricted amd64 Packages [15,0 kB] Get:24 http://dk.archive.ubuntu.com utopic-updates/universe amd64 Packages [14 B] Get:25 http://dk.archive.ubuntu.com utopic-updates/multiverse amd64 Packages [2.645 B] Get:26 http://dk.archive.ubuntu.com utopic-updates/main i386 Packages [14 B] Get:27 http://dk.archive.ubuntu.com utopic-updates/restricted i386 Packages [14,6 kB] Get:28 http://dk.archive.ubuntu.com utopic-updates/universe i386 Packages [14 B] Get:29 http://dk.archive.ubuntu.com utopic-updates/multiverse i386 Packages [2.652 B] Get:30 http://dk.archive.ubuntu.com utopic-updates/main Translation-en [14 B] Get:31 http://dk.archive.ubuntu.com utopic-updates/multiverse Translation-en [10,0 kB] Get:32 http://dk.archive.ubuntu.com utopic-updates/restricted Translation-en [14 B] Get:33 http://dk.archive.ubuntu.com utopic-backports/restricted Sources [14 B] Hit http://dk.archive.ubuntu.com utopic-backports/restricted Translation-en Hit http://dk.archive.ubuntu.com utopic-backports/universe Translation-en Get:34 http://dk.archive.ubuntu.com utopic/restricted Sources [575 B] Get:35 http://dk.archive.ubuntu.com utopic/restricted amd64 Packages [18,4 kB] Get:36 http://dk.archive.ubuntu.com utopic/universe amd64 Packages [8.000 kB] Hit http://dk.archive.ubuntu.com utopic-backports/main Sources Hit http://dk.archive.ubuntu.com utopic-backports/universe Sources Hit http://dk.archive.ubuntu.com utopic-backports/multiverse Sources Hit http://dk.archive.ubuntu.com utopic-backports/main amd64 Packages Hit http://dk.archive.ubuntu.com utopic-backports/restricted amd64 Packages Hit http://dk.archive.ubuntu.com utopic-backports/universe amd64 Packages Hit http://dk.archive.ubuntu.com utopic-backports/multiverse amd64 Packages Hit http://dk.archive.ubuntu.com utopic-backports/main i386 Packages Hit http://dk.archive.ubuntu.com utopic-backports/restricted i386 Packages Hit http://dk.archive.ubuntu.com utopic-backports/universe i386 Packages Hit http://dk.archive.ubuntu.com utopic-backports/multiverse i386 Packages Get:37 http://dk.archive.ubuntu.com utopic/universe Sources [8.345 kB] Err http://dk.archive.ubuntu.com utopic/main amd64 Packages 404 Not Found [IP: 194.19.194.51 80] Err http://dk.archive.ubuntu.com utopic/main i386 Packages 404 Not Found [IP: 194.19.194.51 80] Err http://dk.archive.ubuntu.com utopic/restricted i386 Packages 404 Not Found [IP: 194.19.194.51 80] Err http://dk.archive.ubuntu.com utopic/universe i386 Packages 404 Not Found [IP: 194.19.194.51 80] Err http://dk.archive.ubuntu.com utopic/multiverse i386 Packages 404 Not Found [IP: 194.19.194.51 80] Hit http://dk.archive.ubuntu.com utopic/multiverse Translation-en Hit http://dk.archive.ubuntu.com utopic/restricted Translation-en Get:38 http://dk.archive.ubuntu.com utopic/universe Translation-en [19,5 MB] Get:39 http://dk.archive.ubuntu.com utopic-updates/universe Translation-en [5.776 B] Get:40 http://dk.archive.ubuntu.com utopic-backports/main Translation-en Get:41 http://dk.archive.ubuntu.com utopic-backports/multiverse Translation-en Hit http://dk.archive.ubuntu.com utopic/main Translation-en Fetched 32,3 MB in 10min 11s (52,8 kB/s) W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/restricted/source/Sources Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/main/binary-amd64/Packages 404 Not Found [IP: 194.19.194.51 80] W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/main/binary-i386/Packages 404 Not Found [IP: 194.19.194.51 80] W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/restricted/binary-i386/Packages 404 Not Found [IP: 194.19.194.51 80] W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/universe/binary-i386/Packages 404 Not Found [IP: 194.19.194.51 80] W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic/multiverse/binary-i386/Packages 404 Not Found [IP: 194.19.194.51 80] W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/source/Sources Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/restricted/source/Sources Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/binary-amd64/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/restricted/binary-amd64/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/universe/binary-amd64/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/multiverse/binary-amd64/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/main/binary-i386/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/restricted/binary-i386/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/universe/binary-i386/Packages Hash Sum mismatch W: Failed to fetch http://dk.archive.ubuntu.com/ubuntu/dists/utopic-updates/multiverse/binary-i386/Packages Hash Sum mismatch E: Some index files failed to download. They have been ignored, or old ones used instead. jeggy@Jeggy-XPS:~$ 为什么会发生这种情况，以及如何解决这个问题？ 我正在运行Ubuntu 14.10
镜像更新时，这可能只是一种竞争条件。 你也可能在透明代理背后，即使你不知道它。
无论如何，只需等待几个小时或过夜，然后再试一次。
如果错误仍然存在，您可以更改到另一个存储库（例如… us.archive.ubuntu.com …）或删除/var/lib/apt/lists目录中以前下载的索引文件。
我对ru服务器有同样的问题。
LaunchPad上有一个错误： https ： //bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1394494
目前的解决方法是切换到主服务器：
要么您的互联网有问题，要么服务器临时关闭。 你可以再试一次。
您可以检查是否可以使用wget访问服务器：
wget http://dk.archive.ubuntu.com/
更新：如果其他人遇到此问题，我通过使用以下内容替换/etc/apt/sources.list的内容来修复我的问题：
deb http://us.archive.ubuntu.com/ubuntu/ vivid main deb http://us.archive.ubuntu.com/ubuntu/ vivid-updates main
…然后运行sudo apt-get dist-upgrade 。
我测试了美国服务器，但它没有用。 测试了一些荷兰服务器并且没有工作，有许多ubuntu服务器无法工作或不可用。 虽然Ubuntu可以选择寻找最好的工作和可用的服务器。 现在它有效。
sudo update-manager
然后选择选项卡Ubuntu Software – > Downloaded from – > other – > Select Best server
现在它确实有效
