Similar to viewtopic.php?f=309&t=152514

Can someone help me with this:

I have recently upgraded to Kubuntu 20.04 from 18.04 and I notice that some system apps like discover and system settings are not opening only. While some others like Okular, Dolphin, Konsole are working perfectly.

I have posted a sample screen recording at https://imgur.com/a/KlRhpjC to understand the issue better. A surrounding window having an outline shows up but then nothing happens. Attaching logs when `systemsettings5` and `plasma-discover` are opened from the command line. Command automatically goes into the background after some time. I have tried uninstalling KDE and reinstalling but the issue persists.

Currently I am using Awesome window manager but this issue is with Gnome, KDE, dwm and i3 window managers.

Logs for `systemsettings5`:

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$ systemsettings5 # Launching system settings, automatically goes into background.
QQmlEngine::setContextForObject(): Object already has a QQmlContext
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = systemsettings5 path = /usr/bin pid = 8921
KCrash: Arguments: /usr/bin/systemsettings5
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 systemsettings5
$ fg
systemsettings5
QSocketNotifier: Invalid socket 7 and type 'Read', disabling...
QSocketNotifier: Invalid socket 8 and type 'Read', disabling...
Unable to start Dr. Konqi
Re-raising signal for core dump handling.
Segmentation fault (core dumped)

For `plasma-discover`:

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~$ plasma-discover
qrc:/qml/Feedback.qml:2:1: module "org.kde.userfeedback" is not installed
invalid kns backend! "/usr/share/knsrcfiles/ksysguard.knsrc" because: "Config group not found! Check your KNS3 installation."
adding empty sources model QStandardItemModel(0x555f24b444c0)
org.kde.plasma.libdiscover: Couldn't find a category for  "fwupd-backend"
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = plasma-discover path = /usr/bin pid = 143304
KCrash: Arguments: /usr/bin/plasma-discover
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0

[1]+  Stopped                 plasma-discover
~[1]$ fg
plasma-discover
QSocketNotifier: Invalid socket 7 and type 'Read', disabling...
QSocketNotifier: Invalid socket 18 and type 'Read', disabling...
Unable to start Dr. Konqi
Re-raising signal for core dump handling.
Segmentation fault (core dumped)


My system configuration:

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$ plasmashell --version
plasmashell 5.18.5
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.1 LTS
Release:        20.04
Codename:       focal


I am a bit puzzled, are you sure the applications are not already running in the background?

Also I am a bit surprised you do not actually use Plasma as your Window manager, the whole point of Kubuntu is to provide a complete Plasma desktop....

From the pastes above you seem to have an incomplete/unfinished installation of Plasma, how about running a full update and upgrade from the command line, followed by

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dpkg --configure -a

Hi, thanks for reply.

are you sure the applications are not already running in the background?

I didn't get anything after running `pgrep plasma`. So I think it is not already running in background.

I am a bit surprised you do not actually use Plasma as your Window manager

I used to use KDE/Plasma as my DE but then I tried tiling window managers and I liked them way more suitable for my usage. So now sticking to it. Although I do like many KDE apps and still use them like Dolphin, Konsole etc. Sometimes I use system settings to configure stuff but until I was on 18.04 everything was working fine. When I upgraded to 20.04, KDE system settings, discover and other apps stopped working.

how about running a full update and upgrade from the command line

I have tried following commands but still didn't get any success

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sudo add-apt-repository ppa:kubuntu-ppa/backports
sudo apt update && sudo apt full-upgrade
sudo apt install plasma-desktop
sudo apt install kubuntu-desktop

What else can I do? Please suggest. Thanks.

did you run my suggestion?

Oh yes, my bad forgot to add it. I also ran `dpkg --configure -a` at the end, but again running `plasma-discover` was throwing same error.

Also some of my system configuration I didn't mention are as follows. I will append them to main post.

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$ plasmashell --version
plasmashell 5.18.5
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 20.04.1 LTS
Release:        20.04
Codename:       focal