我有个问题。
安装软件包或更新系统是不可能的。
终端和软件管理器都无法工作（软件管理器未启动）。
终端显示命令如下：
sudo apt-get update
E: Type 'non-free' is not known on line 3 in source list /etc/apt/sources.list
E: The list of sources could not be read.
当我尝试安装程序时：
sudo apt-get install exfat-utils exfat-fuse
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package exfat-utils is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'exfat-utils' has no installation candidate
E: Unable to locate package exfat-fuse
sudo apt-get update && sudo apt-get install autokey-gtk
E: Type 'non-free' is not known on line 3 in source list /etc/apt/sources.list
E: The list of sources could not be read.
sudo apt-get install autokey-gtk
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package autokey-gtk
我的源列表文件的内容如下：
#deb cdrom:[Linux Mint 17.3 _Rosa_ - Release amd64 20151128]/ trusty contrib
main non-free
deb http://xnv4.xandros.com/xs2.0/upkg-srv2 etch main contrib
non-free
deb http://xnv4.xandros.com/xs2.0/upkg-srv2 etch main contrib
non-free
这个问题在我之前的 Linux Mint (17.0) 上出现过，并在安装 LM 17.3 几周后再次出现。
非常感谢您的帮助，我很感激！
答案1
你的sources.list格式不正确。 “非自由”不应出现在单独的行上。这就是您看到的原因：
E: Type 'non-free' is not known on line 3 in source list /etc/apt/sources.list
sources.list 应如下所示：
#deb cdrom:[Linux Mint 17.3 _Rosa_ - Release amd64 20151128]/ trusty main contrib non-free
deb http://xnv4.xandros.com/xs2.0/upkg-srv2 etch main contrib non-free
deb http://xnv4.xandros.com/xs2.0/upkg-srv2 etch main contrib non-free
另请注意，您的第一行已被注释掉，因此您实际上只有两行，这两行看起来都不像 Mint 的标准源。您可能想添加更多来源。还要考虑是否要保留xnv4.xandros.com来源。