package dovecot-core 1:2.2.18-2ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

[Andre Cusson]

window freeze when "open shell ... to consider ..." option was selected, with "next"

ProblemType: Package
DistroRelease: Ubuntu 15.10
Package: dovecot-core 1:2.2.18-2ubuntu2
ProcVersionSignature: Ubuntu 3.19.0-33.38-lowlatency 3.19.8-ckt7
Uname: Linux 3.19.0-33-lowlatency x86_64
ApportVersion: 2.19.1-0ubuntu5
Architecture: amd64
Date: Fri Nov 20 23:15:04 2015
DpkgHistoryLog:

DpkgTerminalLog:

ErrorMessage: subprocess installed post-installation script returned error exit status 1
InstallationDate: Installed on 2015-05-06 (199 days ago)
InstallationMedia: Ubuntu-Studio 15.04 "Vivid Vervet" - Release amd64 (20150422)
RelatedPackageVersions:
 dpkg 1.18.2ubuntu5
 apt 1.0.10.2ubuntu1
SourcePackage: dovecot
Title: package dovecot-core 1:2.2.18-2ubuntu2 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)

[Robie Basak (racb)]

Thank you for taking the time to report this bug and helping to make Ubuntu better.

Unfortunately the bug report automation was not able to include enough information for a developer to understand this problem. If you have any more information you can provide then please include it. Otherwise we'll need to keep this bug marked Incomplete until someone else has the same issue and can provide more information.

[Launchpad Janitor (janitor)]

[Expired for dovecot (Ubuntu) because there has been no activity for 60 days.]

[Bill Thorsteinson (billthor55)]

In my case I traced it to the group dovecot not existing.