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Dataflows validating queries - error message

In power bi service data flow, I loaded excel files from one drive, completed transformations, and when clicked save & close button getting error after 2 minutes of validation.


dataflows error - query loading.png





An error occurred while validating your queries (session ID:a1862deb-dc87-4364-a78c-b122f2b7a7a5).


Could anyone advise what does this means and any suggestions with the next steps? 

Status: New
Advocate IV

@FireFighter1017 because sadly they do a crummy job of cleaning up ideas and requests, I wouldn't always go by the state of the status of ideas or issues. 😞 The issues can come up again and again based on the fact that it's a service based issue. They might just need to fix it again.


Yes when you set up the initial connection to the data source you should be able to specify the column count in the initial data source M code.

Regular Visitor

I'm still having the same issue here even today. Anyone got further solution to this matter?

Helper III

@cvillegas I haven't seen this parameter in Excel.Workbook:



Advocate IV

@FireFighter1017 Yep, looks like they limit the params in Power Query Online vs on the Desktop. There are quite a few fun hidden ones and keep in mind sometimes Power Query Online can differ sometimes from Power Query on the desktop (Excel, PBI Desktop).


To see these try this out:


Source = #shared






Helper III

@cvillegas I finally copied the queries in a pbix, closed all my browser windows, rebooted my computer to get rid of any cached data from Power BI Service.

Then I just used the pbix file I used to backup my queries and applied the changes again and all went ok.


It happenned on other queries I had been working on for a couple of days.  Not the exact same error message, but that some attribute existed more than once or some other nonsense.

The pbix backup proved to be very helpful so far.