Bug 504641

Summary:	System monitor sensor config won't save. Blank widget after reboot (Plasma 6.3.4)
Product:	[Plasma] plasmashell	Reporter:	mcarans <mcarans>
Component:	System Monitor widgets	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED FIXED
Severity:	normal	CC:	ahiemstra, nate, notmart
Priority:	NOR
Version First Reported In:	6.3.4
Target Milestone:	1.0
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed In:	6.4.0
Sentry Crash Report:

Description mcarans 2025-05-21 23:13:18 UTC

SUMMARY
Every time I boot, the system monitor sensors I have set up are gone. This has happened since upgrading to Kubuntu 25.04 which has KDE Plasma 6.3.4. I have tried removing the widget altogether and then adding a new system monitor sensor widget. I've also tried clicking "Save Settings as Preset" but that doesn't make any difference. Is there any way to get them to be retained? 

STEPS TO REPRODUCE
1. Install Kubuntu 25.04
2. Add system monitor widget
3. Set up CPU usage or whatever
4. Reboot

OBSERVED RESULT
Sensors are gone - just a blank System Monitor Sensor widget remains


EXPECTED RESULT
Sensors are retained

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
(available in the Info Center app, or by running `kinfo` in a terminal window)
Linux/KDE Plasma: Kubuntu 25.04
KDE Plasma Version: 6.3.4
KDE Frameworks Version: 6.12.0
Qt Version: 6.8.3

Comment 1 Nate Graham 2025-05-22 14:53:17 UTC

> 3. Set up CPU usage or whatever
Can you please be specific about exactly how you're setting it up? It's possible that this is a key part of what causes the issue.

Comment 2 mcarans 2025-05-22 20:09:02 UTC

(In reply to Nate Graham from comment #1)
> > 3. Set up CPU usage or whatever
> Can you please be specific about exactly how you're setting it up? It's
> possible that this is a key part of what causes the issue.

Thanks for your reply. Here are the steps I tried:

1. Right click on widget
2. Select "Configure System Monitor Sensor..."
3. Under Appearance, choose Display Style "Line Chart" and Apply
4. Under Sensor Details - Sensors click cpu - all - Total Usage (%), cpu - all - Maximum CPU Temperature (C) and memory - physical - Used Physical Memory Percentage (%)
5. Click Apply - sensors appear in widget and are functioning fine
6. Under Appearance, click Save Settings As Preset (I've tried with and without this step)
7. Reboot
8. Sensor(s) are gone

Comment 3 mcarans 2025-05-22 21:13:02 UTC

I posted on r/kubuntu to see if anyone else has this issue and it looks like I am not the only one:
https://www.reddit.com/r/Kubuntu/comments/1ksbnn7/system_monitor_sensors_wont_save_in_2504/

Comment 4 Nate Graham 2025-05-28 19:08:10 UTC

Thank you for the detailed steps! I followed them exactly and cannot reproduce the issue in current git master, which was recently branched for Plasma 6.4. There were indeed some changes to System Monitor sensor saving that went into Plasma 6.4, so it seems that this issue has been fixed.

Comment 5 mcarans 2025-07-20 20:02:22 UTC

Interestingly, I'm still on Plasma 6.3.4 but a recent upgrade (I think of the Nvidia drivers) seems to have fixed it.