# Cron-plus error "System Time Change Detected" and not executing

**URL:** <https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521>\
**Category:** General\
**Created:** [19 October 2024 09:03 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521 "2024-10-19T09:03:54Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![BobUrban](https://avatars.discourse-cdn.com/v4/letter/b/2bfe46/32.png) [@BobUrban](https://discourse.nodered.org/u/BobUrban)\
**Post date:** [19 October 2024 09:03 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/1 "2024-10-19T09:03:54Z")

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Hello,  
I am running NodeRed 4.0.2 on a Pi Model 2B. I have some very simple flow with cronplus nodes that sends mqtt commands. I am getting quite often (not all the time for some weird reason) this error:

`System Time Change Detected - refreshing schedules! If the system time was not changed then this typically occurs due to blocking code elsewhere in your application`

Sometime this even causes the Timers to not get executed.  
I have a DS3231 RTC installed on the Pi, since its offline most of the time.  
Might this cause any issues, if not what might be the problem?

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [19 October 2024 09:14 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/2 "2024-10-19T09:14:15Z")

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I put that in there to let users know that inaccurate cron times can occur if your flows or nodes cause blocking such that nodejs didnt even see the clock change. It turns out to be a handy notification to let you know _something aint right_

Typically, this happens when you have hard processing loops (usually in a function or a contrib node) or heavy processing (like large payloads being manipulated by a node). Do you have any of this going one around the time you see the message?

Keep an eye on your CPU usage - do you see spikes?

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**Author:** ![dceejay](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/dceejay/32/38_2.png) [@dceejay](https://discourse.nodered.org/u/dceejay)\
**Post date:** [19 October 2024 09:15 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/3 "2024-10-19T09:15:52Z")

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@Steve-Mcl - would a time shift due to summer/winter time trigger it also ?

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**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [19 October 2024 09:18 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/4 "2024-10-19T09:18:53Z")

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> [@dceejay](#):
>
> would a time shift due to summer/winter time trigger it also

Yeah. That is initially why it was added - to refresh schedules to ensure they happen at the correct time. Code for ref: [node-red-contrib-cron-plus/cronplus.js at master · Steve-Mcl/node-red-contrib-cron-plus · GitHub](https://github.com/Steve-Mcl/node-red-contrib-cron-plus/blob/master/cronplus.js#L885)

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**Author:** ![BobUrban](https://avatars.discourse-cdn.com/v4/letter/b/2bfe46/32.png) [@BobUrban](https://discourse.nodered.org/u/BobUrban)\
**Post date:** [19 October 2024 10:00 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/5 "2024-10-19T10:00:40Z")

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Thanks, just checked, indeed node red was 100% load on one core.  
So I started disabling some nodes and found out that the contrib valetudo-map-png node seems to be the problem.

> **[node-red-contrib-valetudo](https://flows.nodered.org/node/node-red-contrib-valetudo)**
>
> Node-RED-nodes for valetudo

I will check in the long term if it happens again.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [17 January 2025 10:01 UTC](https://discourse.nodered.org/t/cron-plus-error-system-time-change-detected-and-not-executing/92521/6 "2025-01-17T10:01:23Z")

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