> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/nextseq-500-550/instrumentation-nextseq-500-550-reference_material-list/000002085.md).

# How to enable saving thumbnail images for troubleshooting on the NextSeq 500/550

**Background**

On the NextSeq 500/550, thumbnail images are disabled by default because enabling them can run the risk of affecting Real-Time Analysis (RTA) performance, potentially causing RTA to run slowly or crash. An RTA crash would render the sequencing run unrecoverable.

Saving thumbnail images during runs can be useful during troubleshooting. In certain cases, Illumina support may direct to temporarily enable saving thumbnail images.

**Note**: Do not enable thumbnail images unless directed by Illumina Technical Support. Disable thumbnails after troubleshooting has been completed (see below).

**How to enable/disable thumbnail images**

1. **Close** the NextSeq Control Software (NCS).
   * Being logged into into the sbsuser operating system (OS) account usually works for this. In some cases local IT policy may restrict changing file system names. If so, it may be necessary to log into the sbsadmin OS account to grant the user admin privileges.
2. **Find** the "InstrumentShell.NextSeqControlSoftware.Options.cfg" file:
   1. **Windows 7 file path**:

      * ```
        ```

      C:\Illumina\NextSeq Control Software\InstrumentShell.NextSeqControlSoftware.Options.cfg

      ```
      ```
   2. **Windows 10 file path**:

      * ```
        ```

      C:\ProgramData\*\Illumina\NextSeq Control Software\InstrumentShell.NextSeqControlSoftware.Options.cfg

      ```
      ```
3. In case the working file becomes corrupted, **duplicate** this file and name the backup file "InstrumentShell.NextSeqControlSoftwareOptions.cfg.BAK" and **Save**
4. **Open** the original file in NotePad and find the line with the argument:

   * ```
     ```

   \<RtaSaveThumbnails>false

   ```
   ```
5. **Change** the argument's value to **true**:

   * ```
     ```

   \<RtaSaveThumbnails>true

   ```
   ```
6. **Save** the file.
7. **Power cycle** the system following the steps in the Knowledge Base article [How to Power Cycle the NextSeq 500/550](/instrumentation/general/instrumentation-general-reference_material-list/000001972.md).
8. **Start** NCS and verify it intializes normally

**Once Troubleshooting is Complete**

**Repeat** the above steps to turn thumbnail images OFF by changing the argument's value back from true to false. Save the file, power cycle and verify NCS can initialize.

**NOTE:** For Windows 10, in order to access the ProgramData folder, **Hidden Items** must be enabled first. Open File Explorer, navigate to **View**, and then make sure **Hidden Items** is selected.

![](/files/nF07hLDhQP2pDZsf8RWR)

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #2085), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000002085%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |


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