package roundcube-core 1.2~beta+dfsg.1-0ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Robert Cates]

A "simple" dist-upgrade from 14.04.x to 16.04.1 caused this error/problem.

ProblemType: Package
DistroRelease: Ubuntu 16.04
Package: roundcube-core 1.2~beta+dfsg.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.1
Architecture: amd64
Date: Fri Jul 29 05:09:23 2016
ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2015-11-09 (262 days ago)
InstallationMedia: Xubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
PackageArchitecture: all
RelatedPackageVersions:
 dpkg 1.18.4ubuntu1.1
 apt 1.2.12~ubuntu16.04.1
SourcePackage: roundcube
Title: package roundcube-core 1.2~beta+dfsg.1-0ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: Upgraded to xenial on 2016-07-29 (0 days ago)

[Jun Inquig (juninquig)]

I have the same problem when I upgraded from 14.04 to 16.04. The instruction is to run apt-get -f install and I got this error which obviously is very alien for me as a newbie. Any help will be appreciated. Thank you.

The following packages will be upgraded:
  roundcube roundcube-core
2 upgraded, 0 newly installed, 0 to remove and 18 not upgraded.
2 not fully installed or removed.
Need to get 0 B/1,930 kB of archives.
After this operation, 5,036 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Preconfiguring packages ...
(Reading database ... 324894 files and directories currently installed.)
Preparing to unpack .../roundcube-core_1.2~beta+dfsg.1-0ubuntu1_all.deb ...
dpkg-maintscript-helper: error: directory '/var/lib/roundcube/config' contains files not owned by package roundcube-core:all, cannot switch to symlink
dpkg: error processing archive /var/cache/apt/archives/roundcube-core_1.2~beta+dfsg.1-0ubuntu1_all.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
Reinstalling /etc/roundcube/db.inc.php that was moved away
dbconfig-common: flushing administrative password
dpkg: considering deconfiguration of roundcube-core, which would be broken by installation of roundcube ...
dpkg: yes, will deconfigure roundcube-core (broken by roundcube)
Preparing to unpack .../roundcube_1.2~beta+dfsg.1-0ubuntu1_all.deb ...
De-configuring roundcube-core (0.9.5-4) ...
dpkg-maintscript-helper: error: directory '/usr/share/doc/roundcube' contains files not owned by package roundcube:all, cannot switch to symlink
dpkg: error processing archive /var/cache/apt/archives/roundcube_1.2~beta+dfsg.1-0ubuntu1_all.deb (--unpack):
 subprocess new pre-installation script returned error exit status 1
dbconfig-common: flushing administrative password
Errors were encountered while processing:
 /var/cache/apt/archives/roundcube-core_1.2~beta+dfsg.1-0ubuntu1_all.deb
 /var/cache/apt/archives/roundcube_1.2~beta+dfsg.1-0ubuntu1_all.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Martin Brunner (mbrunner1337)]

Hi,
I experienced the exact same issue as described above.
Likewise it suggested to run apt-get -f install after which I ended up with the same error as described above.

The following did the trick for me:

1) make sure that the files in the directories it is complaining about have either the correct permissions and owner (e.g., "www-data") or move them temporarily such that the folders are empty:

the 2 relevant messages / directories are :
dpkg-maintscript-helper: error: directory '/var/lib/roundcube/config' contains files not owned by package roundcube-core:all, cannot switch to symlink

dpkg-maintscript-helper: error: directory '/usr/share/doc/roundcube' contains files not owned by package roundcube:all, cannot switch to symlink

2)Manually (re)install the roundcube-core package as follwos (order is important due to dependencies):

dpkg --auto-deconfigure -i /var/cache/apt/archives/roundcube-core_1.2~beta+dfsg.1-0ubuntu1_all.deb

3)Manually (re)install the roundcube package as follows:
 dpkg --auto-deconfigure -i /var/cache/apt/archives/roundcube_1.2~beta+dfsg.1-0ubuntu1_all.deb

4) adapt / overwrite your (pre-)existing configs if necessary/appropriate,
 enter your data / credentials in the subsequent dialog, reload services and be (hopefully) happy again :-)