# Why am I getting this as an error

**URL:** <https://discourse.nodered.org/t/why-am-i-getting-this-as-an-error/13881>\
**Category:** General\
**Created:** [31 July 2019 21:52 UTC](https://discourse.nodered.org/t/why-am-i-getting-this-as-an-error/13881 "2019-07-31T21:52:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [31 July 2019 21:52 UTC](https://discourse.nodered.org/t/why-am-i-getting-this-as-an-error/13881/1 "2019-07-31T21:52:29Z")

</div>

I have a flow to catch errors.  
This morning I saw there were a few. Yes, something was happening, but why I got this error is confusing.

```auto
{"delay":"18000","payload":"2019-8-1 07:39:18 up 27 minutes\n","_msgid":"a9dafd22.a65de","_event":"node:94f35468.443b9","time":"2019-8-1 07:39:19","filename":"/media/pi/9020-9C27/logs/last_alive.db","error":"2019-8-1 07:39:18 up 27 minutes\n","topic":"ERROR_REPORT/TelePi/Local Readings/undefined","ttl":0,"_queuetimestamp":1564609159433,"_queueCount":11}

```

Why is it an error?

I am not seeing anything "wrong" with it.

The "thing that was happening:  
When I got up, that machine's LED was flickering.  
Looking at my dashboard, it was not responding to pings.  
It wasn't connected to my WAP either.

I rebooted it. (Alas power cycle.)

Somewhere along the way the USB stick I have plugged in became read only.  
I tested it and couldn't write to it.  
I unplugged it and checked it on my main machine. It wasn't.  
Plugged it back in, and all was sweet.

As I was "leaving", I saw that there was a flow error detected.

That's what I saw/got.

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<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [31 July 2019 21:55 UTC](https://discourse.nodered.org/t/why-am-i-getting-this-as-an-error/13881/2 "2019-07-31T21:55:48Z")

</div>

`"topic":"ERROR_REPORT/TelePi/Local Readings/undefined"`

Undefined usually ends up as an error.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [31 July 2019 22:06 UTC](https://discourse.nodered.org/t/why-am-i-getting-this-as-an-error/13881/3 "2019-07-31T22:06:18Z")

</div>

Yeah, ok.

That explains it.

The USB stick decided to become `/dev/sdb1` rather than `/dev/sda1` as it was before I unplugged it, or it became **read only**.

And wasn't there for a while as I was testing if it was read only on my other machine.

Thanks.