after upgrading to 17.04 and, maybe, running out of disk space, a further upgrade fails

[Alain]

Fetched 38.5 MB in 6s (3'434 kB/s)

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done

Calculating the changes

Calculating the changes

Could not calculate the upgrade

An unresolvable problem occurred while calculating the upgrade.

This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: ubuntu-release-upgrader-core 1:17.04.10
ProcVersionSignature: Ubuntu 4.10.0-42.46-generic 4.10.17
Uname: Linux 4.10.0-42-generic x86_64
NonfreeKernelModules: zfs zunicode zavl zcommon znvpair
ApportVersion: 2.20.4-0ubuntu4.9
Architecture: amd64
CrashDB: ubuntu
Date: Mon Jan 1 18:08:01 2018
InstallationDate: Installed on 2014-05-27 (1314 days ago)
InstallationMedia: Mythbuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
UpgradeStatus: Upgraded to zesty on 2018-01-01 (0 days ago)

[ZdravkoG (zdravko-g)]

Probably same problem: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1743995

[Alain (alain-xen)]

The problem must have been related to one or more specific packages which were blocking the upgrade. I have removed a number of packages and the problem went away.

The bug I would tag is the complete lack of useful information: why couldn't calculate the upgrade? At which package did it fail? How about a way to trace the execution to narrow down the problem?

That is what should be fixed.