Troubleshooting Wash State Unknown in NextSeq 500/550 Control Software (NCS) v4.0.0

The following warning can appear in NextSeq Control Software (NCS) v4.0.0 after the instrument is rebooted and initialized. The NextSeq Control Software prompts a notification mentioning the wash state is unknown and then allows for either proceeding with a wash or no wash. This error is specific to NCS 4.0.0 and was fixed in Control Software update v4.0.1.

Troubleshooting steps:

• Update the NextSeq Control Software from v4.0.0 to v4.0.1.

• Contact Illumina Technical Support for any additional questions.

For any feedback or questions regarding this article (Illumina Knowledge Article #2114), contact Illumina Technical Support [e-mail].