Dataflow Gen 2 Error:MashupException.Error:Expression.Error: We cannot convert a value of type List

[Thyagarajulu99]

Hi Team,

I created the Dataflow Gen2, which connects to the Azure Synapse On-Demand Database Server and refreshes the Lakehouse Delta tables using existing views on the server.

However, the Dataflow Gen2 is failing with the following error for a table:

'There was a problem refreshing the dataflow: Couldn't refresh the entity because of an issue with the mashup document. MashupException.Error: Expression.Error: We cannot convert a value of type List to type Table. Details: Reason = Expression.Error; ErrorCode = 10276; Value = {[...], [...]}'. Error code: Mashup Exception Expression Error.

Kindly help me to understand this issue.

[Anonymous · Accepted solution]

Hi @Thyagarajulu99 ,

The error message indicates that Dataflow Gen2 is trying to convert a List to a Table, which is an invalid operation. You can use the Table.FromList function to correctly convert a List to a Table.

let
    MyList = {1, 2, 3, 4, 5},
    MyTable = Table.FromList(MyList, Splitter.SplitByNothing(), null, null, ExtraValues.Error)
in
    MyTable

For more details, you can refer to below document:

Table.FromList - PowerQuery M | Microsoft Learn

Best Regards,
Adamk Kong

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.