# How to turn on thumbnails for troubleshooting on the NextSeq 500/550

Turning on thumbnail images on the NextSeq 500/550 can affect Real Time Analysis (RTA) speed.

On the NextSeq 500/550, thumbnail images are disabled by default to prevent Real Time Analysis (RTA) from running slowly and/or crashing (from which a sequencing run cannot be recovered).

Thumbnail images can be helpful in troubleshooting, and can be enabled with the following steps.

1. Close the NextSeq Control Software.

* sbsuser login works for this (unless local IT restricted access to update files and sbsadmin account login is necessary).

2. Open the 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. Find the line:

* ```
  <RtaSaveThumbnails>false</RtaSaveThumbnails>  
  ```

4. Change it to true:

* ```
  <RtaSaveThumbnails>true</RtaSaveThumbnails>  
  ```

5. Save the file.
6. Power cycle the system.

\\\***Note**: 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/qRcL2kPJy6lV30spTpNg)

Once troubleshooting activities are complete the thumbnail images can be **turned off** by following the above directions and changing **true** to **false** in the config file and saving the file.

For further information, search for Knowledge Base article **How to Perform a NextSeq 500/550 Power Cycle.**

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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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