# Error using DOCKER & Rancher Desktop

**URL:** <https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987>\
**Category:** Dashboard\
**Tags:** docker\
**Created:** [12 May 2026 08:49 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987 "2026-05-12T08:49:49Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![PinPat](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@PinPat](https://discourse.nodered.org/u/PinPat)\
**Post date:** [12 May 2026 08:49 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/1 "2026-05-12T08:49:49Z")

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I have just started working with Docker and Rancher Desktop. I have imported my flows from previous window's version. The last time i used the NCD devices were two-three years ago.  
Now when i am running flows, i am getting error message in RANCHER mynodered log as " [Error: Error: No such file or directory, cannot open COM4] ". I have connected NCD wireless mega modem using USB on my laptop. How can i resolve this issue?

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**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [12 May 2026 10:49 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/2 "2026-05-12T10:49:53Z")

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This is not uncommon when using USB/Serial ports. They have a tendency to change port. This is even more likely on Windows but can still happen on Linux as well.

You will need to know what COM port the device is connected to now and then adjust Docker to use that port. Since you can map ports in your Docker config, I think that the correct approach would be to use a fixed port inside Docker but adjust the hosts port and restart the Docker instance.

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<div class="post-metadata">

**Author:** ![PinPat](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@PinPat](https://discourse.nodered.org/u/PinPat)\
**Post date:** [12 May 2026 13:19 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/3 "2026-05-12T13:19:58Z")

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Hi, still getting same error. if you can guide with few commands, would be appreciated.

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/0/8/08fd9b84f2db6d0ff7351774da2e9b16bd401ee9.png)

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [12 May 2026 14:17 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/4 "2026-05-12T14:17:27Z")

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What com port is your modem on?

What is the Docker configuration of your Node-RED container?

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<div class="post-metadata">

**Author:** ![PinPat](https://avatars.discourse-cdn.com/v4/letter/p/ad7895/32.png) [@PinPat](https://discourse.nodered.org/u/PinPat)\
**Post date:** [12 May 2026 14:31 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/5 "2026-05-12T14:31:38Z")

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modem on com4.  
we are just running docker in powershell. what type of configurataion should i do and how?

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<div class="post-metadata">

**Author:** ![TotallyInformation](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/totallyinformation/32/31_2.png) [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Post date:** [12 May 2026 15:02 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/6 "2026-05-12T15:02:56Z")

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Are you using the standard Node-RED container? That uses Linux. To get Windows COM ports to mount as Linux USB devices takes some work.

I've not done this as I don't run Node-RED in Docker on any platform. However, there appear to be articles online to help:

> <https://stackoverflow.com/questions/69467148/acces-windows-com-port-from-dockerlinux-container>

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [11 June 2026 15:03 UTC](https://discourse.nodered.org/t/error-using-docker-rancher-desktop/100987/7 "2026-06-11T15:03:36Z")

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