Bug 517081 - Wallpaper changing and the "Apply plasma settings" features don't work when there's an old /var/lib/plasmalogin folder left over from earlier versions
Summary: Wallpaper changing and the "Apply plasma settings" features don't work when t...
Status: RESOLVED FIXED
Alias: None
Product: plasma-login-manager
Classification: Plasma
Component: general (other bugs)
Version First Reported In: 6.6.2
Platform: Arch Linux Linux
: HI normal
Target Milestone: ---
Assignee: Plasma Bugs List
URL:
Keywords: regression
: 522822 (view as bug list)
Depends on:
Blocks:
 
Reported: 2026-03-04 12:18 UTC by johnweak-dev
Modified: 2026-08-05 02:30 UTC (History)
9 users (show)

See Also:
Latest Commit:
Version Fixed/Implemented In: 6.7.4
Sentry Crash Report:


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Description johnweak-dev 2026-03-04 12:18:37 UTC
SUMMARY

apply plasma settings doesn't apply anything, my screen layout is not the same as the one I have setup, the theme didn't apply and numlock isn't enabled on start

STEPS TO REPRODUCE
1. go to system settings
2. go login screen
3. click "apply plasma settings"

EXPECTED RESULT

should apply my screen layout, my numlock preference and my theme

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: 6.18.13-zen1-1-zen (64 bit)
KDE Plasma Version: 6.6.2
KDE Frameworks Version: 6.23.0
Qt Version: 6.10.2
Comment 1 Sky Poincet 2026-06-25 18:19:15 UTC
Can reproduce on KDE Linux (2026-06-25 13:10).
The "Apply" and "Reset to default settings" options both seem to not trigger an update of `/etc/plasmalogin.conf` (does not modify nor create the file). Also persists after manually deleting the file (in case of wrong file permissions) while applying a wallpaper from "Configure Appearance..." does modify the file (and create it if needed).
The only log line when doing so is the authentication prompt with a generic Qt warning.
```
kf.auth: Action "org.kde.kcontrol.kcmplasmalogin.sync" has no parentWindow, assuming QWidgetWindow(0x5630974501b0, name="MainWindow#1Window")
```

Operating System: KDE Linux 2026-06-25
KDE Plasma Version: 6.7.80
KDE Frameworks Version: 6.28.0
Qt Version: 6.11.1
Kernel Version: 7.0.12-arch1-1 (64-bit)
Graphics Platform: Wayland
Comment 2 Sky Poincet 2026-06-25 19:09:45 UTC
Figured out there's also configuration in /var/lib/plasmalogin for the plasmalogin sysuser, sorry for the wrong directions.
Seems like deleting the folder, letting the system recreate plasmalogin's home, and then doing things on the KCM actually ends up applying the settings.
Before doing so, I checked a bit and it seems the settings where applied (same plasmaglobalsrc as my user for exemple) but PLM didn't actually read them. So there could be a permission issue inherited from old versions (my KDE Linux install was from before the transition from SDDM to PLM and must have gone through regressed builds which broke something) and could not have gotten remediated automatically.
Comment 3 Nate Graham 2026-06-27 17:38:59 UTC
Can you confirm this, johnweak-dev? Do you have a folder named /var/lib/plasmalogin on your system, and does it help to delete it and restart the system?
Comment 4 zxl 2026-06-28 10:16:43 UTC
(In reply to Nate Graham from comment #3)
> Can you confirm this, johnweak-dev? Do you have a folder named
> /var/lib/plasmalogin on your system, and does it help to delete it and
> restart the system?

I'm not the OP but had the exact same issue (also former SDDM that got transitioned to PLM).
Deleting `/var/lib/plasmalogin` + reboot solved the issue.
Comment 5 inimicus 2026-07-12 15:36:25 UTC
I have the same problem as OP, also SDDM migrated to PLM, but removing /var/lib/plasmalogin and rebooting did not solve the issue. Neither did uninstalling, cleaning up any leftover files and reinstalling the package.
Comment 6 Nate Graham 2026-07-17 20:41:58 UTC
*** Bug 522822 has been marked as a duplicate of this bug. ***
Comment 7 Oliver Beard 2026-07-20 10:13:15 UTC
Git commit ab16cf42b2f49303f7c177ec4ff2f1ce3f405884 by Oliver Beard, on behalf of David Edmundson.
Committed on 20/07/2026 at 10:13.
Pushed by olib into branch 'master'.

kcm: Fix wallpaper permissions

Plasmalogin manager changed how the authentication system worked in
7b4a086c71779ebf4df80a2f681928cfeba3bf87. Instead of running as root,
the authentication helper switched user to the plasmalogin user to run
actions.

For clean setups this all works fine, but any stale configuration files
from 6.6 that are root owned now cannot be overridden.

Perform a migration fix in the helper.
Related: bug 521008

M  +93   -0    src/frontend/kcm/auth/plasmaloginauthhelper.cpp
M  +3    -0    src/frontend/kcm/auth/plasmaloginauthhelper.h

https://invent.kde.org/plasma/plasma-login-manager/-/commit/ab16cf42b2f49303f7c177ec4ff2f1ce3f405884
Comment 8 Oliver Beard 2026-07-20 10:30:14 UTC
Git commit 0eaeacd11c1341038c958bca062cf6c973eed271 by Oliver Beard.
Committed on 20/07/2026 at 10:14.
Pushed by olib into branch 'Plasma/6.7'.

kcm: Fix wallpaper permissions

Plasmalogin manager changed how the authentication system worked in
7b4a086c71779ebf4df80a2f681928cfeba3bf87. Instead of running as root,
the authentication helper switched user to the plasmalogin user to run
actions.

For clean setups this all works fine, but any stale configuration files
from 6.6 that are root owned now cannot be overridden.

Perform a migration fix in the helper.
Related: bug 521008


(cherry picked from commit ab16cf42b2f49303f7c177ec4ff2f1ce3f405884)

bbe4418e kcm: Fix wallpaper permissions

Co-authored-by: David Edmundson <kde@davidedmundson.co.uk>

M  +93   -0    src/frontend/kcm/auth/plasmaloginauthhelper.cpp
M  +3    -0    src/frontend/kcm/auth/plasmaloginauthhelper.h

https://invent.kde.org/plasma/plasma-login-manager/-/commit/0eaeacd11c1341038c958bca062cf6c973eed271