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I'm not sure what I pressed or clicked but I can no longer see the taskbar in KDE. I'm not finding any desktop switching keys though ALT+Tab still switches to already opened windows. Right-clicking on the blank empty black background does nothing. On Windows 7 I'd just CTRL+ALT+Delete, kill explorer.exe and start explorer again.

How do I show the missing taskbar in KDE?

John
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7 Answers7

42

Killing the plasmashell process and restarting it from a terminal helped me in this situation.

To terminate the plasmashell process you will need access to a terminal. On most distributions you can get a terminal with CTRL+ALT+F1 or CTRL+ALT+F2. Don't worry, your screen will turn black and you will be prompted to log in with your username and password.

To get back to your regular KDE session you will need to press CTRL+ALT+F7 or CTRL+ALT+F1!

Once you have opened a terminal session you can stop the plasmashell process with 

killall plasmashell

and start it again with 

plasmashell &

The & is only required if you want to be able to close the terminal or want to be able to keep using it for other commands. It will start the plasmashell process in the background so it does not close with the terminal and does not keep blocking the terminal from receiving further input.

Alternatively you can kill the plasmashell process in your terminal and then immediately return to KDE and hit your hotkey for krunner, which is afaik ALT+F2 by default, and enter plasmashell there.

FlyingFoX
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  • ...I probably did not accept this answer because it lacked/lacks instructions. If someone is asking a question an answer should provide instructions. – John Sep 07 '18 at 09:55
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    That can be fixed :) – FlyingFoX Sep 11 '18 at 16:17
  • Thank you, I up-voted this, looks legitimate though since I'm no longer running that environment I can't technically accept it...right now. It might be a year down the line though with Microsoft busy destroying the parts of Windows that actually still works I'll eventually find some time to explore a hopefully even more matured Linux OS. KDE has been my preferred desktop environment. – John Sep 12 '18 at 12:57
  • I've stumbled upon a very similar phenomenon, but restarting plasmashell in a shell alone was enough, so this process crashed somehow before. Maybe there is a bug related to or in VSCode, because its small preview windows become very small before the task bar crashes. This happens when you click on the VSCode entry nonetheless. – BairDev Nov 30 '18 at 10:13
  • @John Accept it. It still works! (The answer I mean) – Carlos Rafael Ramirez Oct 17 '19 at 07:28
  • @CarlosRafaelRamirez I am not in a position to **verify** that it works though I will very likely be sometime in the 1H of 2020. I'll literally be paying someone to fix a LOT of the GUI/UX issues in Linux at some point next year and thus far prefer KDE. I still update blog articles and pages on my sites that are over a decade old. Not forgotten, it *will* happen. ︀ – John Oct 17 '19 at 13:12
  • For me, it was a temporary solution. When I restarted the problem came again. Ultimately I had to delete the cache: `rm -rf ~/.cache` – Carlos Rafael Ramirez Oct 18 '19 at 15:20
41

In my case the ~/.config/plasma-org.kde.plasma.desktop-appletsrc file got in a bad state (from switching from laptop to external monitor).

Rather than trying to fix the file, I just deleted it (ALT-F2 "konsole"):

rm ~/.config/plasma-org.kde.plasma.desktop-appletsrc

Then logout from the session (ALT-F2 "logout") Log back in, and the taskbar is now visible, some settings were lost (background color, ...)

I now personally keep a backup of the file, in case it happens again:

cp ~/.config/plasma-org.kde.plasma.desktop-appletsrc ~/.config/plasma-org.kde.plasma.desktop-appletsrc.backup
xx1xx
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  • Brilliant, thank you! Any tips on how to avoid it happening again? – bdeniker Jan 24 '20 at 09:07
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    Reboots, killing plasma shell, etc. didn't work for me either. But this one did for me too :) Thank you! – HBSKan Mar 21 '20 at 16:31
  • It worked on Kubuntu 19.10. Thank you – Alex Poca Apr 10 '20 at 20:07
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    I had removed a videocard, going from three to one monitor. This answer gave me a fresh new taskbar, but my menu panel was still gone. What I then did was edit my own file (no, had not deleted it, but moved it out of the way) and ran: `sed -i -e 's/^lastScreen=.*/lastScreen=0/' ~/.config/plasma-org.kde.plasma.desktop-appletsrc` - then logged out and back in and got everything back as it was. – Carlo Wood May 07 '20 at 19:18
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    Happened for me as well when (dis)connecting an external display. Removing the file fixed the issue. Thanks! – Tom Pohl Jun 27 '22 at 09:17
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don't trust KDE plasma desktop, after you're happy with your widget setup backup the config

mv ~/.config/plasma-org.kde.plasma.desktop-appletsrc ~/.config/plasma-org.kde.plasma.desktop-appletsrc.bak

now to fix your problem delete the corrupted config

rm ~/.config/plasma-org.kde.plasma.desktop-appletsrc

then restart the kde

qdbus org.kde.ksmserver /KSMServer logout 0 0 0

whenever this happens replace your config with the current one this happens a lot to me sometimes when I connect dual monitor

Fathy
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2

As I faced exactly the same issue on my notebook with Intel+Nvidia Optimus (proprietary driver), my solution is to add

xrandr --output VGA-0 --off

to /usr/share/sddm/scripts/Xsetup

Though removing ~/.config files is a default reaction, it didn't solve my problem. Anyway I'd recommend renaming configuration files if needed for testing purposes:

mv ~/.config/plasma-org.kde.plasma.desktop-appletsrc ~/.config/plasma-org.kde.plasma.desktop-appletsrc.bkp

It is a known bug that nvidia drivers add CTR device VGA-0 even if it is not connected. So this caused plasmashell to crash at login time. A quite comprehensible reaction to such a noobish bug IMHO.

I also tried to disable VGA-0 in KDE Display Settings, but these settings come into effect after login. Xsetup is run before sddm starts, so the CTR device is disabled even before startplasmashell-X11 which is executed by /usr/share/xsessions/plasma.desktop

Hope this helps to solve it without plasmashell --replace & because that command slows down login time, plus grinded my nerves.

Cheers

domson
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  • Thanks a lot! Your post was the end to a more-than-one-hour long bughunt! I don't think I would have found the issue without your post! – Dakkaron Apr 30 '22 at 20:23
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You can reinstall the plasma-desktop to use KDE again:

sudo apt-get reinstall plasma-desktop

Alternatively you can use the dpkg-reconfigure to reconfig your plasma desktop:

sudo dpkg-reconfigure plasma-desktop

This is a problem for some kde updates.

http://bugs.launchpad.net/ubuntu/+source/kdeadmin/+bug/331192/

mashuptwice
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Cool_Geek
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1

I also do the backup of ~/.config/plasma-org.kde.plasma.desktop-appletsrc to restore on the odd occasion things really break but sometimes all you need is to get back a missing panel (including taskbars) or widget by doing the following:

  1. Show the desktop (e.g. Meta + D)
  2. Put the desktop into edit mode (Alt + D then E, or right-click and select)
  3. Click the Manage Desktops And Panels button that appears at the top of the screen
  4. Drag and drop any items from disabled screens/outputs to your enabled one(s)

It's quicker and less hassle as it doesn't require you to kill programs/log out & in.

Walf
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1

To reload the Plasma desktop if something got hung up somehow in the current session:

plasmashell --replace &

To re-add the default panel if it permanently got lost, i.e. if even reloading Plasma or logging out and in again doesn't help:

Right-click on desktop -> Add Panel -> Default Panel.

Natalie Clarius
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