Skip to main content
Showing results for 
Search instead for 
Did you mean: 

Register now to learn Fabric in free live sessions led by the best Microsoft experts. From Apr 16 to May 9, in English and Spanish.

New Member

Expression.Error: The index cannot be negative

Hi All, 


Maybe you can help me with this error. I was running Power Query a lot of times and did not have this error. 

Now it showed up and I am not able to find where is the issue with it. 


An error occurred in the ‘Test Dataview’ query. Expression.Error: The index cannot be negative.


And it happens after this step 

= Table.NestedJoin(Custom1, {"PRODUCT NUMBER/ SKU"}, #"SKU Price bracket", {"Sku #"}, "SKU Price bracket", JoinKind.LeftOuter)


Dataview query is loading without any issues or errors. 


Can someone please help or let me know where I should look for solution. Thanks!

Community Support
Community Support

Hi @Zoru ,

The error message suggests that a list is being accessed with an index of -1, which is invalid. Review any steps in your query that involve list indexing or operations that might result in a negative index.
Ensure that the columns specified in the function exist and contain the expected data. A mismatch or unexpected null values could potentially lead to issues.

Best Regards,

Community Support Team


If there is any post helps, then please consider Accept it as the solution  to help the other members find it more quickly.
If I misunderstand your needs or you still have problems on it, please feel free to let us know. Thanks a lot!

How to get your questions answered quickly --  How to provide sample data in the Power BI Forum -- China Power BI User Group

Helper III
Helper III

Please investigate both tables before joining. Error may appear on this step, but it doesn't mean that this is caused by this step.


JestedJoin reads all the data to perform the operation. Therefore, it will load all the rows, where you might have errors which don't appear in Previews (where you deal with limitted data). Try go to both tables from before join, and use Table.SelectRowsWithErrors function to find the step which is causing your error.

Super User
Super User

Do you have null values in the join column for the left table?

Helpful resources

Microsoft Fabric Learn Together

Microsoft Fabric Learn Together

Covering the world! 9:00-10:30 AM Sydney, 4:00-5:30 PM CET (Paris/Berlin), 7:00-8:30 PM Mexico City


Power BI Monthly Update - April 2024

Check out the April 2024 Power BI update to learn about new features.

April Fabric Community Update

Fabric Community Update - April 2024

Find out what's new and trending in the Fabric Community.

Top Solution Authors
Top Kudoed Authors