package daemontools-run 1:0.76-6ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

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

From TerminalLog.txt:

Setting up daemontools (1:0.76-6ubuntu1) ...
Setting up daemontools-run (1:0.76-6ubuntu1) ...
Adding SV inittab entry...
start: Job is already running: svscan

I found a workaround to this issue and logged it here: https://bugs.launchpad.net/ubuntu/+source/daemontools/+bug/1617691/comments/4

I got the package situation resolved that was caused due to performing a 14.04->16.04 LTS upgrade.

I removed the following packages:
dnscache-run
daemontools-run

Then reinstalled them from the raw .deb files I had downloaded to the server.

$sudo dpkg -i daemontools-run_0.76-6ubuntu1_all.deb
$sudo dpkg -i dnscache-run_1.05-8ubuntu1_all.deb

I didn't have dnscache-run installed. When I try to install from the raw .deb file I got the same error. But the upgrade tool said it completed successfully except for that error and after rebooting dnscache-run was no longer problematic and lsb_release shows I'm on 16.04, so I think everything is fine.

sudo apt-get install dnscache-run seems to have solved my problem also.

During another 14.04->16.04 LTS upgrade:

Setting up daemontools (1:0.76-6ubuntu1) ...
Setting up daemontools-run (1:0.76-6ubuntu1) ...
Adding SV inittab entry...
start: Job is already running: svscan
dpkg: error processing package daemontools-run (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up dialog (1.3-20160209-1) ...

== DuplicateSignature =================================
package:daemontools-run:1:0.76-6ubuntu1
Setting up daemontools-run (1:0.76-6ubuntu1) ...
Adding SV inittab entry...
start: Job is already running: svscan
dpkg: error processing package daemontools-run (--configure):
 subprocess installed post-installation script returned error exit status 1

== ErrorMessage =================================
subprocess installed post-installation script returned error exit status 1

== Package =================================
daemontools-run 1:0.76-6ubuntu1

== PackageArchitecture =================================
all

== ProblemType =================================
Package

== ProcVersionSignature =================================
Ubuntu 3.13.0-110.157-generic 3.13.11-ckt39

== RelatedPackageVersions =================================
dpkg 1.18.4ubuntu1.1
apt 1.2.19

== SourcePackage =================================
daemontools

== Tags =================================
 xenial

== Title =================================
package daemontools-run 1:0.76-6ubuntu1 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1

== Uname =================================
Linux 3.13.0-110-generic i686

== UpgradeStatus =================================
Upgraded to xenial on 2017-02-25 (0 days ago)

What would you like to do? Your options are:
  S: Send report (419.6 KB)
  V: View report
  K: Keep report file for sending later or copying to somewhere else
  I: Cancel and ignore future crashes of this program version
  C: Cancel
Please choose (S/V/K/I/C):

Issue still present with the 16.04 package being installed over top of the 14.04 package.

Package dnscache-run was not downloaded during the LTS upgrade process, only daemontools-run.

$ ls -al | grep dnscache-run
$ ls -al | grep daemontools-run
-rw-r--r-- 1 root root 6454 Jan 7 2015 daemontools-run_1%3a0.76-6ubuntu1_all.deb

The "usual" uninstall / IPL / reinstall per #4 again was the work-around.