Distribution Upgrade icon stuck in Launcher with no window after running

[teo1978]

When running Software Updater, I started getting the messy, unclear, mostly nonsensical error message that says "Some of the updates couldn't be installed bla bla bla. This could be due to any of the following reasons" (1. you tell me exactly which one; 2. some of them don't even make sense) and I was given the options "Continue" (continue what?) or "Do a partial upgrade" (with no explanation of what a partial upgrade is). That dialog is a complete disaster in the first place.

Anyway, the second time I got this shitty dialog that doesn't explain what has happened and gives no clue about what to do, I chose "Do a partial upgrade", whatever the f**k that means.

When prompted I clicked "ok", "continue" or whatever.

After a few hours, when that had been long finished, I noticed that I couldn't suspend the computer. Suspend just does nothing (no error message either).
Then I noticed that there was this "?" icon in the Launcher. When rolling over it, the tooltip says "Distribution Upgrade". When clicking on it, no window shows up or gets focus.

Even in the Alt-Tab list of supposedly open windows, there is one with the same "?" icon, and clicking on it does nothing.

So, it seems that the Distribution Upgrade is somehow not responding, and also the window manager and/or Launcher are fundamentally broken if they allow an application to have an active and selected icon in Launcher (and in the Alt+Tab menu) without a corresponding window: that's an inconsistency that shouldn't be possible no matter how broken and buggy an application is.

Upgrading stuff is one of the most delicate moments when you most need the system to be absolutely rock-solid, yet it's almost when Ubuntu is most unreliable.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.22
ProcVersionSignature: Ubuntu 4.4.0-83.106-generic 4.4.70
Uname: Linux 4.4.0-83-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
CrashDB: ubuntu
CurrentDesktop: Unity
Date: Mon Aug 7 02:05:11 2017
InstallationDate: Installed on 2013-10-11 (1395 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: dist-upgrade
UpgradeStatus: No upgrade log present (probably fresh install)
VarLogDistupgradeTermlog:

[Launchpad Janitor (janitor)]

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