Databricks ADBC Driver problems after new update

[lesbs]

Hi We wanted to start using the ADBC Driver for performance but are getting this error after the latest Power BI Jan 2026 update. 
What is the recommended action? 

Next to this we noticed big problems with fetching data, posting and running the query from power bi to databricks works fine, after our serverless unit takes hours to fetch the results and send them back to the power bi service, in the end ending up in a timeout error. 

Not sure if the two are related.

Thanx for the help

[Toussaint9]

The root cause of this issue (timeout failures during refresh operations) has been identified and will be resolved in the upcoming Power BI release.

As a short term workaround customers can add the MaxNumResultFileDownloadThreads="1" parameter to their Power BI M-code connection string (or rollback to ODBC).

Example M-code: let Source = Databricks.Catalogs( "your-server.azuredatabricks.net", "/sql/1.0/warehouses/your-warehouse-id", [ Implementation="2.0", MaxNumResultFileDownloadThreads="1" ] ),

[pinar1]

Thank you for the reply, I tried this. However the refresh / refresh preview in the Power Query is lasting forever after I did what you suggested. Is this normal? Anyone having the same problem? 

[sergej_og]

Same here.
Just figured out by setting this option connection works again

[lesbs]

Yes true found that as well, but that basically sets it back to the ODBC driver. Im not sure if this is a bug to report to Microsoft or to Databricks

[sergej_og]

Yes, I assume it's a bug to be reported.
With version of Nov 2025 everything was fine

[v-achippa]

Hi @lesbs,

Thank you for reaching out to Microsoft Fabric Community.

Thank you @Toussaint9 and @sergej_og for the prompt response.

As we haven’t heard back from you, we wanted to kindly follow up to check if your issue is resolved or as the user suggested have you reported it as it is bug?

If not please consider submitting your detailed feedback and ideas through Microsoft's official feedback channels. Feedback submitted through these channels is frequently reviewed by the product teams and can contribute to meaningful improvements.

Fabric Ideas - Microsoft Fabric Community

Thanks and regards,

Anjan Kumar Chippa

[lesbs]

How/where can we get this best reported so its picked up asap? since its quite the issue
on the ideas form is more for new feature suggestions i think?

[MJG]

Definitely still an issue and is not resolved for us- and is a problem for us.

[WorkaroundLover]

Same here. I wonder how long it will take before it is fixed.