大家好，我是讯享网，很高兴认识大家。

新安装的Ubuntu在使用sudo apt-get update更新源码的时候出现如下错误：

W: GPG 错误：http://ppa.launchpad.net precise Release: 由于没有公钥，无法验证下列签名： NO_PUBKEY 3EE66BD3F599ACE3 W: GPG 错误：http://ppa.launchpad.net precise Release: 由于没有公钥，无法验证下列签名： NO_PUBKEY 6AF0EA220 W: 无法下载 bzip2:/var/lib/apt/lists/partial/mirrors.163.com_ubuntu_dists_precise_main_binary-i386_Packages Hash 校验和不符 W: 无法下载 bzip2:/var/lib/apt/lists/partial/mirrors.163.com_ubuntu_dists_precise-security_main_binary-i386_Packages Hash 校验和不符 W: 无法下载 bzip2:/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-amd64_Packages Hash 校验和不符 W: 无法下载 bzip2:/var/lib/apt/lists/partial/extras.ubuntu.com_ubuntu_dists_precise_main_binary-i386_Packages Hash 校验和不符 E: Some index files failed to download. They have been ignored, or old ones used instead. 

讯享网
解决方法很简单，下载导入公钥就行，下载导入key的命令如下：

讯享网sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 6AF0EA220 #此处6AF0EA220需要是错误提示的key

此时继续更新发现没有公钥错误提示，但是还是效验存在问题，此时需要打开软件源的界面，将其他软件选项中的Canpnical合作伙伴/独立等四个选项取消勾选，再执行sudo apt-get update

讯享网

此时发现可以顺利更新了。

sanbo@ubuntu:~/dev$ sudo apt-get update 命中 http://mirrors.163.com precise Release.gpg 命中 http://mirrors.163.com precise-updates Release.gpg 命中 http://mirrors.163.com precise-security Release.gpg 命中 http://mirrors.163.com precise Release 命中 http://mirrors.163.com precise-updates Release 命中 http://mirrors.163.com precise-security Release 命中 http://mirrors.163.com precise/main Sources 命中 http://mirrors.163.com precise/restricted Sources 命中 http://mirrors.163.com precise/universe Sources 命中 http://mirrors.163.com precise/multiverse Sources 命中 http://mirrors.163.com precise/main amd64 Packages 命中 http://mirrors.163.com precise/restricted amd64 Packages 命中 http://mirrors.163.com precise/universe amd64 Packages 命中 http://mirrors.163.com precise/multiverse amd64 Packages 命中 http://mirrors.163.com precise/main i386 Packages 命中 http://mirrors.163.com precise/restricted i386 Packages 命中 http://mirrors.163.com precise/universe i386 Packages 命中 http://mirrors.163.com precise/multiverse i386 Packages 命中 http://mirrors.163.com precise/main TranslationIndex 命中 http://mirrors.163.com precise/multiverse TranslationIndex 命中 http://mirrors.163.com precise/restricted TranslationIndex 命中 http://mirrors.163.com precise/universe TranslationIndex 命中 http://mirrors.163.com precise-updates/main Sources 命中 http://mirrors.163.com precise-updates/restricted Sources 命中 http://mirrors.163.com precise-updates/universe Sources 命中 http://mirrors.163.com precise-updates/multiverse Sources 命中 http://mirrors.163.com precise-updates/main amd64 Packages 命中 http://mirrors.163.com precise-updates/restricted amd64 Packages 命中 http://mirrors.163.com precise-updates/universe amd64 Packages 命中 http://mirrors.163.com precise-updates/multiverse amd64 Packages 命中 http://mirrors.163.com precise-updates/main i386 Packages 命中 http://mirrors.163.com precise-updates/restricted i386 Packages 命中 http://mirrors.163.com precise-updates/universe i386 Packages 命中 http://mirrors.163.com precise-updates/multiverse i386 Packages 命中 http://mirrors.163.com precise-updates/main TranslationIndex 命中 http://mirrors.163.com precise-updates/multiverse TranslationIndex 命中 http://mirrors.163.com precise-updates/restricted TranslationIndex 命中 http://mirrors.163.com precise-updates/universe TranslationIndex 命中 http://mirrors.163.com precise-security/main Sources 命中 http://mirrors.163.com precise-security/restricted Sources 命中 http://mirrors.163.com precise-security/universe Sources 命中 http://mirrors.163.com precise-security/multiverse Sources 命中 http://mirrors.163.com precise-security/main amd64 Packages 命中 http://mirrors.163.com precise-security/restricted amd64 Packages 命中 http://mirrors.163.com precise-security/universe amd64 Packages 命中 http://mirrors.163.com precise-security/multiverse amd64 Packages 命中 http://ppa.launchpad.net precise Release.gpg 命中 http://ppa.launchpad.net precise Release.gpg 命中 http://mirrors.163.com precise-security/main i386 Packages 命中 http://mirrors.163.com precise-security/restricted i386 Packages 命中 http://mirrors.163.com precise-security/universe i386 Packages 命中 http://mirrors.163.com precise-security/multiverse i386 Packages 命中 http://mirrors.163.com precise-security/main TranslationIndex 命中 http://mirrors.163.com precise-security/multiverse TranslationIndex 命中 http://mirrors.163.com precise-security/restricted TranslationIndex 命中 http://mirrors.163.com precise-security/universe TranslationIndex 获取：1 http://mirrors.163.com precise/main Translation-zh_CN [100 kB] 命中 http://mirrors.163.com precise/main Translation-en 获取：2 http://mirrors.163.com precise/multiverse Translation-zh_CN [6,476 B] 命中 http://mirrors.163.com precise/multiverse Translation-en 获取：3 http://mirrors.163.com precise/restricted Translation-zh_CN [2,620 B] 命中 http://mirrors.163.com precise/restricted Translation-en 获取：4 http://mirrors.163.com precise/universe Translation-zh_CN [139 kB] 命中 http://ppa.launchpad.net precise Release 命中 http://mirrors.163.com precise/universe Translation-en 获取：5 http://mirrors.163.com precise-updates/main Translation-zh_CN [100 kB] 命中 http://mirrors.163.com precise-updates/main Translation-en 获取：6 http://mirrors.163.com precise-updates/multiverse Translation-zh_CN [6,476 B] 命中 http://mirrors.163.com precise-updates/multiverse Translation-en 获取：7 http://mirrors.163.com precise-updates/restricted Translation-zh_CN [2,620 B] 命中 http://mirrors.163.com precise-updates/restricted Translation-en 获取：8 http://mirrors.163.com precise-updates/universe Translation-zh_CN [139 kB] 命中 http://mirrors.163.com precise-updates/universe Translation-en 命中 http://mirrors.163.com precise-security/main Translation-en 命中 http://mirrors.163.com precise-security/multiverse Translation-en 命中 http://mirrors.163.com precise-security/restricted Translation-en 命中 http://mirrors.163.com precise-security/universe Translation-en 命中 http://ppa.launchpad.net precise Release 命中 http://ppa.launchpad.net precise/main Sources 命中 http://ppa.launchpad.net precise/main amd64 Packages 命中 http://ppa.launchpad.net precise/main i386 Packages 忽略 http://ppa.launchpad.net precise/main TranslationIndex 命中 http://ppa.launchpad.net precise/main Sources 命中 http://ppa.launchpad.net precise/main amd64 Packages 命中 http://ppa.launchpad.net precise/main i386 Packages 忽略 http://ppa.launchpad.net precise/main TranslationIndex 忽略 http://ppa.launchpad.net precise/main Translation-zh_CN 忽略 http://ppa.launchpad.net precise/main Translation-zh 忽略 http://ppa.launchpad.net precise/main Translation-en_US 忽略 http://ppa.launchpad.net precise/main Translation-en 忽略 http://ppa.launchpad.net precise/main Translation-zh_CN 忽略 http://ppa.launchpad.net precise/main Translation-zh 忽略 http://ppa.launchpad.net precise/main Translation-en_US 忽略 http://ppa.launchpad.net precise/main Translation-en 下载 497 kB，耗时 7秒 (66.3 kB/s) 正在读取软件包列表... 完成 

搞定收工！

另外送上一个163源，更新的速度挺不错，品种也挺全的:

讯享网# deb cdrom:[Ubuntu 12.04.1 LTS _Precise Pangolin_ - Release i386 (.3)]/ precise main restricted # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to # newer versions of the distribution. deb http://mirrors.163.com/ubuntu/ precise main restricted deb-src http://mirrors.163.com/ubuntu/ precise main restricted Major bug fix updates produced after the final release of the distribution. deb http://mirrors.163.com/ubuntu/ precise-updates main restricted deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu team. Also, please note that software in universe WILL NOT receive any review or updates from the Ubuntu security team. deb http://mirrors.163.com/ubuntu/ precise universe deb-src http://mirrors.163.com/ubuntu/ precise universe deb http://mirrors.163.com/ubuntu/ precise-updates universe deb-src http://mirrors.163.com/ubuntu/ precise-updates universe N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu team, and may not be under a free licence. Please satisfy yourself as to your rights to use the software. Also, please note that software in multiverse WILL NOT receive any review or updates from the Ubuntu security team. deb http://mirrors.163.com/ubuntu/ precise multiverse deb-src http://mirrors.163.com/ubuntu/ precise multiverse deb http://mirrors.163.com/ubuntu/ precise-updates multiverse deb-src http://mirrors.163.com/ubuntu/ precise-updates multiverse N.B. software from this repository may not have been tested as extensively as that contained in the main release, although it includes newer versions of some applications which may provide useful features. Also, please note that software in backports WILL NOT receive any review or updates from the Ubuntu security team. deb http://mirrors.163.com/ubuntu/ precise-security main restricted deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted deb http://mirrors.163.com/ubuntu/ precise-security universe deb-src http://mirrors.163.com/ubuntu/ precise-security universe deb http://mirrors.163.com/ubuntu/ precise-security multiverse deb-src http://mirrors.163.com/ubuntu/ precise-security multiverse Uncomment the following two lines to add software from Canonical's 'partner' repository. This software is not part of Ubuntu, but is offered by Canonical and the respective vendors as a service to Ubuntu users. deb http://archive.canonical.com/ubuntu precise partner deb-src http://archive.canonical.com/ubuntu precise partner This software is not part of Ubuntu, but is offered by third-party developers who want to ship their latest software. deb http://extras.ubuntu.com/ubuntu precise main deb-src http://extras.ubuntu.com/ubuntu precise main # codeblock deb http://ppa.launchpad.net/pasgui/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/pasgui/ppa/ubuntu precise main # ubuntu tweak deb http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main deb-src http://ppa.launchpad.net/tualatrix/ppa/ubuntu precise main

==============================================偶尔时刻还是有各种问题，归纳如下================================================

 【缺少公钥】

现象：

sudo apt-get update W: GPG error: http://apt.tt-solutions.com dapper Release: 由于没有公钥，下列签名无法进行验证： NO_PUBKEY 06EA41DE4F6C1E86

解决方法：

讯享网gpg --keyserver subkeys.pgp.net --recv 4F6C1E86 gpg --export --armor 4F6C1E86 | sudo apt-key add -

说明：
若缺少其他公钥，则将命令中两处4F6C1E86改为NO_PUBKEY
06EA41DE4F6C1E86中最后8位即可！

如果是Ubuntu PPA的则按照如下方法处理：

sudo apt-key adv --recv-keys --keyserver keyserver.ubuntu.com

情况一.概率出现的问题，这次有，可能下次就没了，可忽略

讯享网By simply waiting. This happens at times during archive updates.

情况二.使用如下方法更新：

$ sudo apt-get update -o Acquire::http::No-Cache=True 或者 $ sudo apt-get update -o Acquire::BrokenProxy=true

情况三.
现象：

讯享网In a particular case this was caused by a broken file and could get fixed using rescue boot and "fsck -fy /" (http://forum.ubuntuusers.de/goto?post=89197 - german)

解决办法：

fsck -fy /

情况四：

现象：

讯享网The fix is just to back up sources.list, delete everything in it and run "apt-get update". After the update replace sources.list with the backup and run "apt-get update" again. You should not get the error then.

解决办法：

备份sources.list，然后把sources.list中的东西删空，运行"apt-get update"，然后再用刚刚的备份将"apt-get update"复原，再运行"apt-get update"。

情况五.主旨就是清理缓存

sudo bash apt-get clean cd /var/lib/apt mv lists lists.old mkdir -p lists/partial apt-get clean apt-get update

情况六.缓存代理服务器导致的问题：

讯享网Acquire::http::No-Cache "true"; Acquire::http::Max-Age "0";

情况七

sudo apt-get install medibuntu-keyring