# Troubleshooting 'An unexpected error occurred during sequencing' Errors on the MiSeq i100 Series

**Background**

Issues during a sequencing run that the Control Software is not able to categorize will stop the run and present the following generic error message in the Notifications menu:

"An unexpected error occurred during sequencing."

If this issue presents during a sequencing run, please see the following Troubleshooting Actions.

**Troubleshooting Actions**

1. Select **Eject Cartridge**, to remove the dry and wet sequencing cartridges from the instrument.
2. Run the instrument **System Health Checks** using the **Test Cartridges** provided with the instrument.
   1. See Knowledge Article [How to Setup the System Health Checks on the MiSeq i100 Series Instruments](https://knowledge.illumina.com/instrumentation/miseq-i100-series/instrumentation-miseq-i100-series-reference_material-list/000009206) for more information.
3. Once the System Health Checks are complete, select **Clear Checks** and then proceed to the Control Software home screen.
4. Use the **Export Logs - Small** option to bundle the System Health Check results.
   1. Select the affected Sequencing Run from the list when setting up the Export Logs.
   2. See Knowledge Article [How to Export Logs on the MiSeq i100 Series](https://knowledge.illumina.com/instrumentation/miseq-i100-series/instrumentation-miseq-i100-series-reference_material-list/000009265) for more information.
5. Once these actions are completed, contact [Illumina Tech Support](https://www.illumina.com/company/contact-us.html) for next steps.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #9264), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000009264%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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