Power BI Error: Expression.Error: A join operation cannot result in a table with duplicate column na

[jlTos]

Hi. I am trying to understand why I am getting this issue on Power Bi when I have not created a join. This report was working fine until today and I can only assume its a data source issue (File path connection from Zoho Service Desk to Power BI). How can I check this? (I also cannot access the data modeling view in Power Query due to this error)

[rajendraongole1]

Hi @jlTos - The error, “Expression.Error: A join operation cannot result in a table with duplicate column names,” typically arises when Power BI detects duplicate column names during data import or refresh. This can happen even if you haven’t explicitly created a join in Power BIIf there were recent updates in Zoho Service Desk, such as added columns, renamed columns, or duplicate columns with the same name, Power BI might be treating them as duplicates.To investigate, manually export the data from Zoho to an Excel or CSV file, and inspect the structure for any duplicate column names or recent changes.

In Power Query, add a step to remove duplicate columns:

Select Home > Choose Columns, then select only the columns you need, excluding duplicates.

Alternatively, use the Remove Duplicates feature on column names within each query to avoid triggering this error.

If Zoho changed its file path connection or modified API responses (like column names or schema), it could affect Power BI’s data structure recognition. Confirm with Zoho’s support or your Zoho admin if recent updates could affect Power BI integrations.

Hope the above information helps.