Session diagnostics error

Hi Matthew_Martell​,
Thanks for reaching out to the Microsoft Fabric Community forum.

Query Diagnostics is designed to help understand what Power Query is doing during authoring and refresh time. When you start diagnostics, Power Query traces evaluations caused by actions such as refreshing the data preview.

For Query Editor scenarios, you can use Enable in Query Editor under the Diagnostics settings in Power BI Desktop. This allows Query Diagnostics to be used when previewing and authoring without requiring Power BI Desktop to run as administrator.

If you use Start Diagnostics, make sure to select Stop Diagnostics after reproducing the behavior. This allows Power Query to collect and parse the recorded traces.

For more details, please refer to the below Official Microsoft Documentation:
Query diagnostics - Power Query | Microsoft Learn

I hope this helps. Please feel free to reach out if you have any further questions.
Thank you.