Still stuck and cannot upgrade

[Snowhog]

Are you sure your 17.10 system has backports enabled, and is fully up to date?

What steps did you take in trying to upgrade from 17.10 to 18.04? What were the commands you ran?

[GreyGeek]

Just love pkcon!!!

[dequire]

Are you upgrading to a proper Beta 1 .iso, or a daily snapshot? Snapshots are often transitional in nature and more prone to be broken. Either way, I would also ask on #kubuntu-devel on IRC or Telegram as there's often people there involved in those aspects of getting Bionic in shape. If it is an issue, I'm sure they'd like to know about it. One thing that might be noted: On my Neon system, running the latest Plasma, locate shows the following:

james@james-amd-rig:/$ locate *qmlscene*
/home/james/.local/share/flatpak/app/com.kolabnow.kube/x86_64/master/73fd12f9fb85b5d9d99f40fd2155fc67b2cc1d793510b56c6f269f7a88c7d970/files/bin/qmlscene
/snap/kde-frameworks-5/10/usr/bin/qmlscene
/snap/kde-frameworks-5/10/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene
/snap/kde-frameworks-5/13/usr/bin/qmlscene
/snap/kde-frameworks-5/13/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene
/snap/kde-frameworks-5/16/usr/bin/qmlscene
/snap/kde-frameworks-5/16/usr/lib/qt5/bin/qmlscene
/snap/kde-frameworks-5/16/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene
/usr/bin/qmlscene

and looking at the file details:

james@james-amd-rig:~$ pkcon get-details qmlscene
Resolving                     [=========================]         More than one package matches:
Getting details               [=========================]         ain]
Querying                      [=========================]         
Loading cache                 [=========================]         
Finished                      [=========================]         
Package description
package:     qmlscene-5.10.0-0neon+16.04+xenial+build36.amd64
summary:     Qt 5 QML scene viewer
license:     unknown
group:       programming
description: Qt 5 QML scene viewer
size:        39422 bytes
url:         http://qt-project.org/
james@james-amd-rig:~$

It appears that your version of qmlscene appears to be out-dated at this time for the latest Plasma versions, as mine is on 5.10 and you're trying to install 5.9.4. Again, this is on Neon. Also worth noting that on my system, the following have dependencies on version 5.10:

james@james-amd-rig:~$ pkcon depends-on qmlscene
Resolving                     [=========================]         More than one package matches:
Getting dependencies          [=========================]         ain]
Querying                      [=========================]         
Loading cache                 [=========================]         
Finished                      [=========================]         
Installed       libc6-2.23-0ubuntu10.amd64 (installed:ubuntu-xenial-updates-main)       GNU C Library: Shared libraries
Installed       libqt5core5a-5.10.0+dfsg-2+16.04+xenial+build46.amd64 (installed:neon-xenial-main)      Qt 5 core module
Installed       libqt5gui5-5.10.0+dfsg-2+16.04+xenial+build46.amd64 (installed:neon-xenial-main)        Qt 5 GUI module
Installed       libqt5qml5-5.10.0-0neon+16.04+xenial+build36.amd64 (installed:neon-xenial-main) Qt 5 QML module
Installed       libqt5quick5-5.10.0-0neon+16.04+xenial+build36.amd64 (installed:neon-xenial-main)       Qt 5 Quick library
Installed       libqt5widgets5-5.10.0+dfsg-2+16.04+xenial+build46.amd64 (installed:neon-xenial-main)    Qt 5 widgets module
Installed       libstdc++6-5.4.0-6ubuntu1~16.04.9.amd64 (installed:ubuntu-xenial-updates-main)  GNU Standard C++ Library v3
Installed       qtchooser-64-ga1b6736-4+16.04+xenial+build30.amd64 (installed:neon-xenial-main) Wrapper to select between Qt development binary versions
james@james-amd-rig:~$

Are you sure your 17.10 system has backports enabled, and is fully up to date?

[doctordruidphd]

Still unable to upgrade 17.10 -> 18.04.

It is hanging trying to install qt5 stuff. The problem appears to be that it is looking for a file that it is erasing prior to looking for it. The conundrum goes like this:

root@Crynfyd:/# dpkg -i --force-all /var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb
(Reading database ... 762329 files and directories currently installed.)
Preparing to unpack .../qmlscene_5.9.4-0ubuntu1_amd64.deb ...
Unpacking qmlscene (5.9.4-0ubuntu1) over (5.9.1-4ubuntu1) ...
dpkg: error processing archive /var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb (--install):
unable to install new version of '/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene': No such file or directory
Errors were encountered while processing:
/var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb

Apparently it wants to see the file /usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene before it installs. OK, then:

root@Crynfyd:/# touch /usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene
root@Crynfyd:/# file /usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene
/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene: empty

File is there, albeit empty. Then try again:

root@Crynfyd:/# dpkg -i --force-all /var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb
(Reading database ... 762329 files and directories currently installed.)
Preparing to unpack .../qmlscene_5.9.4-0ubuntu1_amd64.deb ...
Unpacking qmlscene (5.9.4-0ubuntu1) over (5.9.1-4ubuntu1) ...
dpkg: error processing archive /var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb (--install):
unable to install new version of '/usr/lib/x86_64-linux-gnu/qt5/bin/qmlscene': No such file or directory
Errors were encountered while processing:
/var/cache/apt/archives/qmlscene_5.9.4-0ubuntu1_amd64.deb

And so it goes on ...

I tried copying the stuff from 17.10 into the new directory, but it just erases everything before it tries the install.

This goes on for about 6 different files before it gives up completely:

Errors were encountered while processing:
/tmp/user/0/apt-dpkg-install-yMiE22/0-qmlscene_5.9.4-0ubuntu1_amd64.deb
/tmp/user/0/apt-dpkg-install-yMiE22/1-qt5-qmake-bin_5.9.4+dfsg-0ubuntu4_amd64.deb
/tmp/user/0/apt-dpkg-install-yMiE22/2-qttools5-dev-tools_5.9.4-0ubuntu1_amd64.deb
/tmp/user/0/apt-dpkg-install-yMiE22/3-qtbase5-dev-tools_5.9.4+dfsg-0ubuntu4_amd64.deb
/tmp/user/0/apt-dpkg-install-yMiE22/4-qt5-assistant_5.9.4-0ubuntu1_amd64.deb
/tmp/user/0/apt-dpkg-install-yMiE22/5-qdbus-qt5_5.9.4-0ubuntu1_amd64.deb

This really seems brain dead - that it's erasing a file it wants to see. And not sure why it needs to see the file anyway, if it's just going to install over it.