Reports in Power BI service fails with with a type mismatch Data source error

Products

• Clarity PPM SaaS

Issue/Introduction

Power BI reports that refresh successfully in Power BI Desktop are consistently failing to refresh in the Power BI Service, specifically encountering "Type mismatch errors." This issue is primarily observed with larger reports that source data from multiple tables. The exact error message from the refresh history states: "Data source error: The following system error occurred: Type mismatch. Table: ODATA Interproject Dependencies."

Environment

Clarity 16.3.2

Cause

The Power BI Service's data refresh engine is generally less tolerant of underlying data source inconsistencies or changes compared to Power BI Desktop. This heightened sensitivity often leads to type mismatch errors when data types inferred by Power BI Desktop diverge from the actual data types encountered during a refresh in the Service, especially with large datasets or complex data models.

Resolution

To resolve this issue, explicitly change the data types for string fields that contain date values within your Power Query editor.