Upgrade trusty -> xenial failed - blank screen

[gerry_the_hat]

My upgrade partly failed. Upgrade manager prepared the upgrade, downloaded the packages and went thru the installation and setup phase. During this phase, the display just blanked. The laptop was not shut down. Thought the system freezed, as I was completely locked out - no switch to console possible, nor a ssh login from another system.

Solution:
Hard reset and boot. The system booted at least, but no X, nor network connection working, just a console. A "dpkg --configure -a" resumed the setup and completed successfully. Reboot and now I have a smooth Xenial system :-)

During the preparation I got a warning about a running screensaver and xclock - something and a possible lockout. The screensaver was actually disabled, but a process was running. Just killed it and proceeded.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-release-upgrader-core 1:16.04.8
ProcVersionSignature: Ubuntu 4.4.0-14.30-generic 4.4.5
Uname: Linux 4.4.0-14-generic x86_64
NonfreeKernelModules: nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
CrashDB: ubuntu
Date: Sat Mar 19 14:20:48 2016
InstallationDate: Installed on 2014-02-26 (751 days ago)
InstallationMedia: Xubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016)
PackageArchitecture: all
SourcePackage: ubuntu-release-upgrader
Symptom: ubuntu-release-upgrader
UpgradeStatus: Upgraded to xenial on 2016-03-19 (0 days ago)
VarLogDistupgradeTermlog:

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/1559463

[Kev Bowring (flocculant)]

Didn't get blank screen during the numerous tests I have done - all I've managed to get was a hung screen :)

Anyway - after waking up and dpkg --configuring all the various vm's have now upgraded.

(Thanks for the report and on the tracker.)

[Launchpad Janitor (janitor)]

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

[gerry_the_hat (gerry-the-hat)]

Well, found out that two screensavers were installed - the old xscreensaver and the new light locker. I'm not sure yet, but thought about that the two caused the trouble. For some unknown reasons, the old xcreensaver didn't get uninstalled from my previous upgrades from the last couple of years. Have seen complaints and bug reports for this. So, might the case that at least one of them was active while doing the upgrade... However, this does not explain why there was no switch into a console possible.

As far as I have seen from the logs attached, the upgrade just stopped...

[Erick Brunzell (lbsolost)]

This may be a duplicate of bug #1549067 which I encountered during Ubuntu GNOME Beta 1 testing.

[Yuri (linux-colombi)]

Same issue while upgrading, as well as trying to install 16.04 from a fresh USB UNetBootin dongle. Found a work-around: switch from HDMI connection to DVI: I saw the installation screen.