# Error creating runner from config: can not convert 'object' into 'string' accessing 'diskio.include\_devices.0'

**URL:** <https://discuss.elastic.co/t/error-creating-runner-from-config-can-not-convert-object-into-string-accessing-diskio-include-devices-0/383533>\
**Category:** Beats\
**Tags:** metricbeat\
**Created:** [November 19, 2025, 1:24pm UTC](https://discuss.elastic.co/t/error-creating-runner-from-config-can-not-convert-object-into-string-accessing-diskio-include-devices-0/383533 "2025-11-19T13:24:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![willemdh](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/willemdh/32/16922_2.png) [@willemdh](https://discuss.elastic.co/u/willemdh)\
**Post date:** [November 19, 2025, 1:24pm UTC](https://discuss.elastic.co/t/error-creating-runner-from-config-can-not-convert-object-into-string-accessing-diskio-include-devices-0/383533/1 "2025-11-19T13:24:14Z")

</div>

Hello,

As I noticed a lot of

`”Could not return any performance counter values for \.\Y: .Error: Incorrect function.”`

For the diskio dataset, I tried setting:

 ![image](https://us1.discourse-cdn.com/elastic/original/3X/6/2/629d88e8498fa6b404a4b4860c8b9e54110acf46.png)

But this results in:

Error creating runner from config: can not convert 'object' into 'string' accessing 'diskio.include\_devices.0'

After which there are no more diskio metrics at all.

Willem

---

<div class="post-metadata">

**Author:** ![Tortoise](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tortoise/32/147587_2.png) [@Tortoise](https://discuss.elastic.co/u/Tortoise)\
**Post date:** [November 21, 2025, 1:17pm UTC](https://discuss.elastic.co/t/error-creating-runner-from-config-can-not-convert-object-into-string-accessing-diskio-include-devices-0/383533/2 "2025-11-21T13:17:35Z")

</div>

Hello @willemdh

We see below error message in the log if we use C: , D: as part of the include disks.

```auto
Unit state changed system/metrics-default-system/metrics-system-9e6d7bd9-3dba-435f-9cc3-a17f41799bdf (STARTING->FAILED): can not convert 'object' into 'string' accessing 'diskio.include_devices.0

```

Below is the documentation :

> **[System diskio metricset | Beats](https://www.elastic.co/docs/reference/beats/metricbeat/metricbeat-metricset-system-diskio)**
>
> The System diskio metricset provides disk IO metrics collected from the operating system. One event is created for each disk mounted on the system. This...

For the Windows you can use the processor as shown below which will only pick records for D: & drop other records as it seems we cannot specify the drive as part of devices.

 ![image](https://us1.discourse-cdn.com/elastic/original/3X/2/6/26fe9af23e9ee6873882d2be1676d4285a7f526e.png)

Thanks!!