Dataflow Gen 1 does not open, fails with Error Code 500

Hi kstiegler ,
Thank you for reaching out to the Microsoft fabric community forum and providing detailed context and diagnostic information.

Currently no reported service outages affecting Dataflow Gen1 on August 4, 2025, according to the Microsoft Fabric service status page. Please note that some intermittent or regional issues may not appear on the public dashboard, especially if they are brief or limited in scope.

We appreciate your approach in consolidating your queries, as this aligns with best practices for Gen1 dataflows, particularly when working with multiple references to the same Dataverse source. Complex dependencies between queries can sometimes cause refresh instability or backend issues, especially with query folding, so simplifying the logic as you have often leads to better reliability and performance.

Regarding the intermittent Error Code 500 when opening or editing the dataflow, this usually indicates a platform issue related to metadata or UI rendering. If the error persists, we recommend submitting a support ticket with the Activity ID, Correlation ID, timestamp, and cluster URI for further investigation.

We also suggest considering a migration to Dataflow Gen2 for improved stability, diagnostics, and performance.

Hope this helps. Please reach out for further assistance.

Thank you.