# Troubleshooting Stalled or Frozen Sequencing Runs on the MiSeq i100 Series

**Background**

The MiSeq i100 Series uses two onboard computers to handle the user interface and process sequencing run data separately. If the computer handling data processing becomes unresponsive during a sequencing run, it can lead to the sequencing run appearing to stall or freeze without completing. If this is observed, see the following **Troubleshooting Actions** and contact [Illumina Tech Support](https://www.illumina.com/company/contact-us.html).

**Troubleshooting Actions**

1. If instrument is configured to copy data to a **local network** or **Cloud storage**, monitor output folder from a separate computer for new files to rule out a potential Control Software display issue.
   1. Illumina recommends checking the /\[Output\_Dir]/\[RunID]/Data/Intensities/BaseCalls/L001/ directory for new Cx.1 directories, where `x` is the cycle number.
   2. Ensure that the sequencing run is not performing **Cluster Generation**, **Read Preparation**, or **Paired-end Turnaround** when checking for new files.
   3. See Knowledge Article [Run time estimates for each sequencing step on Illumina sequencing platforms](https://knowledge.illumina.com/instrumentation/general/instrumentation-general-reference_material-list/000001540) for additional details.
2. If no new files are observed over several hours, toggle the **power switch** on the back of the instrument to power down the instrument.
3. Leave instrument powered down for **2 minutes**, then toggle power switch to **ON** and press the power button on the **front bottom-right corner** to boot the instrument.
4. If the instrument successfully initializes, collect the **Export Logs - Medium** and contact [Illumina Tech Support](https://www.illumina.com/company/contact-us.html) for a secure upload link.
   1. See Illumina Knowledge Article [How to Export Logs on the MiSeq i100 Series](https://illumina.lightning.force.com/articles/Knowledge/How-to-Export-Logs-on-the-MiSeq-i100-Series) for additional details.

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