Issues with Expanding Columns in Power BI Dataflows When Importing JSON Files

Hi mh20221111 ,
When importing JSON files into Power BI dataflows, the expand icon may not appear if the column doesn't contain recognizable list or record structures in the initial rows—often due to blank values or inconsistent formatting. In such cases, Power BI doesn't infer a structured type and therefore doesn't offer the expand option. 

A common workaround is to first filter out the null or blank rows so Power BI can detect the underlying structure, after which the expand button typically becomes available. If that doesn’t work, using the Advanced Editor is indeed a viable method—you can manually modify the M code to access and expand the nested records or lists. While it's not the only solution, it's often the most reliable in these edge cases.