Tag Archives: formula firewall

  • Data Privacy and the Formula Firewall in Power BI / Power Query


    Have you ever received any Errors similar to these?


    Formula.Firewall: Query ‘Merge1’ (step ‘Source’) is accessing data sources that have privacy levels which cannot be used together. Please rebuild this data combination.


    Formula.Firewall: Query ‘Query1’ (step ‘Added Custom’) references other queries or steps, so it may not directly access a data source. Please rebuild this data combination.

    This is the blog post where I’ll cover this specific topic to answer 3 questions:

    • WHY does it even exist
    • What triggers this error
    • How to better spot the cause of the error

    Before we start…let’s define one concept / feature: