我在安装软件的时候，需要用到 sudo apt-get update, 但是总是失败，各种fail to fetch xxxxx 404 not found, 然后我点到那个网址里面去，最新的支持是trusty，根本没有xenial的目录，这怎么解决呢？

请把执行sudo apt-get update 之后终端的所有信息贴上来

还有你是否从14.04升级到的16.04？

我是直接装的16.04镜像
root@leo-Lenovo:~# sudo apt-get update
Hit:1 http://mirrors.sohu.com/ubuntu xenial InRelease
Ign:2 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial InRelease
Ign:3 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial Release
Err:4 http://cn.old-releases.ubuntu.com/ubuntu xenial InRelease
Could not resolve 'cn.old-releases.ubuntu.com'
Err:5 http://cn.old-releases.ubuntu.com/ubuntu xenial-updates InRelease
Could not resolve 'cn.old-releases.ubuntu.com'
Err:6 http://cn.old-releases.ubuntu.com/ubuntu xenial-backports InRelease
Could not resolve 'cn.old-releases.ubuntu.com'
Ign:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
Ign:8 http://dl.google.com/linux/chrome/deb stable InRelease
Ign:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:12 http://dl.google.com/linux/chrome/deb stable Release
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Ign:16 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages.diff/Index
Ign:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Ign:22 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
Ign:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Hit:22 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
Ign:22 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Err:7 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 Packages
404 Not Found
Err:9 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main i386 Packages
404 Not Found
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Ign:10 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main all Packages
Ign:22 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
Ign:11 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en_US
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:13 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main Translation-en
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:14 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main amd64 DEP-11 Metadata
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:15 http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial/main DEP-11 64x64 Icons
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Hit:22 http://dl.google.com/linux/chrome/deb stable/main amd64 Packages
Ign:17 http://dl.google.com/linux/chrome/deb stable/main all Packages
Ign:18 http://dl.google.com/linux/chrome/deb stable/main Translation-en_US
Ign:19 http://dl.google.com/linux/chrome/deb stable/main Translation-en
Ign:20 http://dl.google.com/linux/chrome/deb stable/main amd64 DEP-11 Metadata
Ign:21 http://dl.google.com/linux/chrome/deb stable/main DEP-11 64x64 Icons
Reading package lists... Done
W: The repository 'http://ppa.launchpad.net/tualatrix/ppa/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'http://dl.google.com/linux/chrome/deb stable Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: Failed to fetch http://cn.old-releases.ubuntu.com/ubunt ... /InRelease Could not resolve 'cn.old-releases.ubuntu.com'
W: Failed to fetch http://cn.old-releases.ubuntu.com/ubunt ... /InRelease Could not resolve 'cn.old-releases.ubuntu.com'
W: Failed to fetch http://cn.old-releases.ubuntu.com/ubunt ... /InRelease Could not resolve 'cn.old-releases.ubuntu.com'
E: Failed to fetch http://ppa.launchpad.net/tualatrix/ppa/ ... 4/Packages 404 Not Found
E: Failed to fetch http://ppa.launchpad.net/tualatrix/ppa/ ... 6/Packages 404 Not Found
W: Some index files failed to download. They have been ignored, or old ones used instead.

为什么会有这个源。。。。这个源根本不存在好么。。

ubuntu tweak PPA只支持到14.04，所以16.04还是别装ubuntu-tweak了

如果要修改unity设置请用unity-tweak-tool

另外你还是换个源吧，默认的中国源就好

谢谢，我也不知道为什么会有这个源，官网下的镜像，update至今就没成功过，换了其他源也是，总有奇怪的错误，装软件我还是deb吧

ubuntu tweak deb应该也是装不上的，依赖的一个软件包版本太旧，

你在安裝時 掛載 / 的分割區 有沒有 記得勾選 格式化 ?

http://news.softpedia.com/news/ubuntu-t ... 3672.shtml
Ubuntu Tweak Is Now Officially Dead and Buried
Ubuntu Tweak 正式宣佈結束

unity 請改用 unity-tweak-tool
其它 gnome 請改用 gnome-tweak-tool