系统环境：Ubuntu 16.04.3 LTS

Sometimes a Debian or Ubuntu package does not install correctly and can not be uninstalled. The system update is so completely broken that conventional commands, whether apt-get, ability or dpkg, not corrects the problem.

类似的出现如下故障报错

    [root@master]$ apt-get install slapd
    […]
    Preparing to replace slapd 2.4.25-1+b1 (using .../slapd_2.4.25-1.1_i386.deb) ...
    sed: can't read /etc/ldap/slapd.d/cn=config.ldif: No such file or directory
    invoke-rc.d: initscript slapd, action "stop" failed.
    dpkg: warning: subprocess old pre-removal script returned error exit status 2
    dpkg - trying script from the new package instead ...
    sed: can't read /etc/ldap/slapd.d/cn=config.ldif: No such file or directory
    invoke-rc.d: initscript slapd, action "stop" failed.
    dpkg: error processing /var/cache/apt/archives/slapd_2.4.25-1.1_i386.deb (--unpack):
     subprocess new pre-removal script returned error exit status 2
    configured to not write apport reports
    Backing up /etc/ldap/slapd.d in /var/backups/slapd-2.4.25-1.1... done.
    grep: /etc/ldap/slapd.d/cn=config/olcDatabase*: No such file or directory
    sed: can't read /etc/ldap/slapd.d/cn=config.ldif: No such file or directory
    invoke-rc.d: initscript slapd, action "start" failed.
    dpkg: error while cleaning up:
     subprocess installed post-installation script returned error exit status 2
    Errors were encountered while processing:
     /var/cache/apt/archives/slapd_2.4.25-1.1_i386.deb
    E: Sub-process /usr/bin/dpkg returned an error code (1)

解决办法就是：手动删除/var/lib/dpkg/info/下相应的[文件名].*。如上冲突文件是s/var/cache/apt/archives/slapd_2.4.25-1.1_i386.deb，则检索slapd.*。然后mv或者rm相应的文件。
删除后，执行两次sudo apt-get autoremove命令，就会提示没有进程冲突了。

参考文章: How to fix a broken or half installed Debian deb package