dataflow gen1

[remmypocco]

Hi everyone,

I’m facing an issue with Dataflow Gen1 in the Power BI Service related to privacy levels, and I’d appreciate some guidance.

Background

• I built a report in Power BI Desktop

• All transformations were done in Power Query

• All data sources come from the same SharePoint site

• Authentication: Organizational account

• Privacy level: Organizational for all sources

• I used merge and append operations and several other transformations

• The report was published successfully to Power BI Service

• Scheduled refresh works correctly in the Service

The issue

When I go to Power BI Service → Dataflow Gen1 → Edit tables and try to modify or add transformation steps, clicking Save results in the following error:
"Underlying Error Privacy settings don't allow the combining of data from multiple sources in the same query. \n\r To refresh this dataflow you can either edit the queries or you can allow combining data from multiple sources in the Edit queries Options settings. Activity ID 73d7c5df-2f55-3dfd-91bc-3a284b45a996 Time 2026-01-20T16:27:04.8759228Z"

What I’ve checked

• All SharePoint connections use the same site URL

• Privacy level is set to Organizational on all tables

• I am signed in correctly and have access to the SharePoint site

• The dataset refreshes successfully on schedule

• The issue occurs only when editing transformations in the Service, not during refresh

Question

Why does Power BI Service treat this as “combining multiple data sources” when:

• All data comes from the same SharePoint site

• Privacy levels are consistent

• Refresh works without errors
  how can i solve this problem?

[v-karpurapud]

Hi @remmypocco 

We have not received a response from you regarding the query and were following up to check if you had the opportunity to review the information provided. Please feel free to contact us if you have any further questions.

Thank You.

[SaiTejaTalasila]

Hi @remmypocco ,

This occurs due to how the Power Query Data Privacy Firewall is enforced in Power BI Service for Dataflow Gen1, not because of an incorrect privacy configuration.

Even when all sources use the same SharePoint site URL and all queries are set to Organizational, the Service enforces the firewall strictly. When editing tables in the Service, Power Query re-evaluates query boundaries and detects cross-query or cross-partition dependencies (such as query references, reused functions, or staging queries). This is treated as combining data from multiple sources and is therefore blocked.

Unlike Power BI Desktop, Dataflow Gen1 in the Service does not support “Ignore privacy levels”, and the firewall cannot be disabled. As a result, the error typically appears when clicking Save, even if the dataflow refreshed successfully before.

This is a known limitation of Dataflow Gen1, documented under the Power Query Data Privacy Firewall behavior:

https://learn.microsoft.com/power-query/data-privacy-firewall

Thanks,

Sai Teja 

[v-karpurapud]

Hi @remmypocco 

I wanted to check if you’ve had a chance to review the information provided. If you have any further questions, please let us know. Has your issue been resolved? If not, please share more details so we can assist you further.

Thank You.

[Zanqueta]

Hi @remmypocco 

Even though all tables originate from the same SharePoint site and share the same privacy level (Organisational), the Power BI Service engine treats each connection as a separate source within the Dataflow context. Therefore, operations such as Merge or Append can be interpreted as “combining multiple sources,” triggering the message:

Privacy settings don't allow the combining of data from multiple sources in the same query.

---

Why does this happen?

• In Power BI Desktop, privacy settings were defined and respected during publication.

• In Power BI Service, Dataflows use a different engine (Power Query Online), which does not automatically inherit Desktop settings.

• Each table created in the Dataflow is treated as an independent source, even if they share the same SharePoint domain.

---

How to resolve this?

Option 1: Adjust privacy settings in the Dataflow

1. Open the Dataflow in Power BI Service.

2. Navigate to Settings → Privacy Options.

3. Change the setting to Ignore Privacy Levels or Allow combining data from multiple sources.

   • This enables the engine to combine data without applying privacy barriers.

   • Important: Use this option only if you are certain all sources are secure and belong to the same organisation.

Official documentation:

Security roles and permission levels in standard dataflows - Power Query | Microsoft Learn

 Option 2: Restructure the Dataflow

• Instead of creating multiple tables and then performing Merge/Append in the Service, create a single entity that includes all transformations.

• Alternatively, build a staging Dataflow to consolidate data and then reference it in another Dataflow. This avoids combining multiple sources in one step.

---

Why does refresh succeed but editing fails?

• The refresh process uses the published model, which has already been validated.

• Editing in the Service re-evaluates privacy rules in the online engine, which triggers the restriction.

[remmypocco]

Thank you for the reply, 
For option 1 i cant seem to find anything in power bi service about dataflow privacy service, the settings on desktop ignores privacy. 
for option 2 i wont be able to create a single entity that contains all transformation  because for my report i have 4 dimension tables and one fact table. however merging is needed to create some IDs in the fact table to connect with the dimension tables. some dimension table are data i get from sharepoint dropped by client as its not in house data. so everything can be the same source however its the same sharepoint sites.
thank you 

[v-karpurapud]

Hi @remmypocco 
Thank you for reaching out to the Microsoft Fabric community forum.
 

In Dataflow Gen1, this behavior is expected due to how Power Query Online handles data-source privacy. Even if all tables are from the same SharePoint site with identical URLs, credentials, and an Organizational privacy level, the online engine treats each entity in the dataflow as a separate data-source instance.
 

When you edit the dataflow and perform merge or append operations, Power Query Online re-applies privacy rules at edit time and interprets the operation as combining multiple sources. This privacy check does not happen during scheduled refresh, which is why refresh works with the validated mashup while editing can fail with a privacy error.
 

Unlike Power BI Desktop, Dataflow Gen1 does not inherit the “Ignore Privacy Levels” option and does not always provide privacy settings in the Service. Because of this, Gen1 cannot reliably support merges across multiple entities, even when they use the same SharePoint site and matching credentials and privacy levels.

With a standard star schema using separate fact and dimension tables, this is a known architectural limitation of Dataflow Gen1 rather than a configuration problem. The main options are to keep all merge logic in a single query chain with one SharePoint connection (which may not be practical for dimensional models), move merge and ID-generation to Power BI Desktop and use Gen1 dataflows only for ingestion, or migrate to Dataflows Gen2, which has a modern engine and consistent privacy handling.
 

I hope this helps. If you have more questions, feel free to ask and we’ll be glad to assist further.

Best Regards,

Microsoft Fabric Community Support Team.