# Troubleshooting SIPDOWN Errors on the MiSeq

The MiSeq Control Software (MCS) shows a SIPDOWN error if the reagent sippers are not functioning or cannot be lowered to pierce the foil on the reagent cartridge.

* This can be caused by physical obstruction (if the reagent cartridge is not fully inserted or is damaged), a hardware problem with the sipper assembly, or a communication error.
* When present, this error occurs before the run starts, when the sippers first lower, immediately after selecting the start button.
* This error can present in older versions of MCS as an Object Reference error.

  ![](https://761066130-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGM9W2DuBTgEXv1ClCm8H%2Fuploads%2Fgit-blob-e815a5a0683bbc3820d414352223a15ace6ad7fa%2Fimage1.png?alt=media\&token=4320bea9-38fb-4610-907e-bc20fd1bb44a)

**Troubleshooting steps:**

1. Remove and inspect the reagent cartridge:

* Following a SIPDOWN error, the sippers are not lowered into the reagent cartridge. Open the reagent compartment door and verify the reagent cartridge is fully inserted all the way to the back of the instrument chiller compartment.
* Remove the reagent cartridge and verify no damage to the exterior of the cartridge.
* Confirm if reagent foils are pierced.
* Confirm the reagents are fully thawed\*.
* Store the reagent cartridge, PR2 buffer, and the current flow cell in the buffer in the fridge (4°C).

2. Power cycle\*\* instrument to reset communications.
3. After MCS re-initialization, select post-run wash.
4. Perform the post-run wash with a **previously used flow cell and the MiSeq wash cartridge.**

* Often, the run can be re-started with the same consumables. However, if those consumables are used to complete the post-run wash prior to reloading, the run will fail.
* The post-run wash ***MUST*** be completed with previously used consumables and/or wash specific consumables.

5. If there is no indication of damage to the reagent cartridge, and the post-run wash completes successfully, restart the run with the same consumables.
6. If the reagent cartridge looks damaged, contact [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/) and provide the reagent serial number (SN), cartridge lot number, and cartridge expiration date.

For further information, search for the following Knowledge Base articles:\* [**Troubleshooting Sipdown Errors on the MiSeq video**](https://knowledge.illumina.com/instrumentation/miseq/instrumentation-miseq-troubleshooting-list/000006824)**.**

* [**\*Reagent Stability and Thawing Guidelines for MiSeq Sequencing Kits**](https://knowledge.illumina.com/instrumentation/miseq/instrumentation-miseq-reference_material-list/000001674)
* [\*\*How to Power Cycle the MiSeq](https://knowledge.illumina.com/instrumentation/miseq/instrumentation-miseq-reference_material-list/000001894)
* [**\*\*How to Power Cycle the MiSeq Video**](https://knowledge.illumina.com/instrumentation/miseq/instrumentation-miseq-reference_material-list/000005871)
* [**Wash best practices for the MiSeq**](https://knowledge.illumina.com/instrumentation/miseq/instrumentation-miseq-reference_material-list/000001679)

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #1456), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000001679%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |