报错

Err http://mirrors.aliyun.com wheezy-updates/main Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy-updates/contrib Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy-updates/non-free Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy-updates/main i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy-updates/contrib i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy-updates/non-free i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Ign http://mirrors.aliyun.com wheezy-updates/contrib Translation-en_US
Ign http://mirrors.aliyun.com wheezy-updates/contrib Translation-en
Ign http://mirrors.aliyun.com wheezy-updates/main Translation-en_US
Ign http://mirrors.aliyun.com wheezy-updates/main Translation-en
Ign http://mirrors.aliyun.com wheezy-updates/non-free Translation-en_US
Ign http://mirrors.aliyun.com wheezy-updates/non-free Translation-en
Err http://mirrors.aliyun.com wheezy/updates/main Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy/updates/contrib Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy/updates/non-free Sources
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy/updates/main i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy/updates/contrib i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Err http://mirrors.aliyun.com wheezy/updates/non-free i386 Packages
  404  Not Found [IP: 183.61.14.200 80]
Ign http://mirrors.aliyun.com wheezy/updates/contrib Translation-en_US
Ign http://mirrors.aliyun.com wheezy/updates/contrib Translation-en
Ign http://mirrors.aliyun.com wheezy/updates/main Translation-en_US
Ign http://mirrors.aliyun.com wheezy/updates/main Translation-en
Ign http://mirrors.aliyun.com wheezy/updates/non-free Translation-en_US
Ign http://mirrors.aliyun.com wheezy/updates/non-free Translation-en
W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/main/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/contrib/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/non-free/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/main/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/contrib/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy/non-free/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/main/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/contrib/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/non-free/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/main/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/contrib/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian/dists/wheezy-updates/non-free/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/main/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/contrib/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/non-free/source/Sources  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/main/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/contrib/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

W: Failed to fetch http://mirrors.aliyun.com/debian-security/dists/wheezy/updates/non-free/binary-i386/Packages  404  Not Found [IP: 183.61.14.200 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

解决，换源
首先备份源列表:

sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup

而后用gedit或其他编辑器打开:

sudo gedit /etc/apt/sources.list
sudo kate /etc/apt/sources.list
sudo mousepad /etc/apt/sources.list
sudo leafpad /etc/apt/sources.list (13.04版)

替换掉文件中所有的内容，保存编辑好的文件:
网易163更新服务器(广东广州电信/联通千兆双线接入)，包含其他开源镜像：

deb http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ trusty-backports main restricted universe multiverse

然后，刷新列表:

sudo apt-get update

注意：一定要执行刷新

成功解决。
原文地址：https://www.cnblogs.com/webnote/p/5767853.html