# Null Field Name

**URL:** <https://discuss.elastic.co/t/null-field-name/216457>\
**Category:** Logstash\
**Created:** [January 24, 2020, 3:36pm UTC](https://discuss.elastic.co/t/null-field-name/216457 "2020-01-24T15:36:31Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![kdp494](https://avatars.discourse-cdn.com/v4/letter/k/f6c823/32.png) [@kdp494](https://discuss.elastic.co/u/kdp494)\
**Post date:** [January 24, 2020, 3:36pm UTC](https://discuss.elastic.co/t/null-field-name/216457/1 "2020-01-24T15:36:31Z")

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Hello,

I am getting an error message "field name cannot be an empty string" for a number of documents coming into logstash. I am attempting to remove the null fields with a mutate filter:

`mutate { remove_field => ["[]" ] }`

But I am getting an error:

{:exception=\>"Invalid FieldReference: `[]`"}

Is there a specific way to refer to a null field name so I can remove it (or rename it) or is there another method to resolve?

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [February 21, 2020, 3:36pm UTC](https://discuss.elastic.co/t/null-field-name/216457/2 "2020-02-21T15:36:33Z")

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