# Humidity warning during pre run check on the NextSeq 1000/2000 The Humidity specification for the NextSeq 1000/2000 is 20-80% noncondensing relative humidity. If the humidity is outside of this range, the instrument will give a humidity warning. **Error**: "Humidity is outside the expected range. Data quality may be affected. For more information, see the site prep guide."\ ![](https://761066130-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGM9W2DuBTgEXv1ClCm8H%2Fuploads%2Fgit-blob-1e54fe3426f570c1d8447bb65283c9daa18c877e%2Fimage1.jpg?alt=media\&token=d4cf81de-301c-4a30-9d63-09e96271c242) The warning can be acknowledged and the sequencing run will start. However, Illumina cannot guarantee run performance will meet specifications if humidity is outside the specified operating range. * **Relative** **humidity level low < 20%:** impacts fluidic delivery, increases static. * **Relative** **humidity level high > 80%:** potential for condensation to impact imaging. Work with the local facilities team to return the laboratory to the recommended operating specification. See the [NextSeq 1000/2000 Site Prep Guide](https://support-docs.illumina.com/IN/NextSeq10002000/Content/IN/SitePrep/NextSeq1k_2k/Introduction.htm) for additional information. \ \ \
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