I've updated to the new version of Power BI for June 2017 (2.47.4766.542) and since then my report isn't working anymore. It's been working fine for months but since this update, it gives me the following error : an item with the same key has already been added. I've searched for a solution and I've tried many things but none of them worked. I've gone back to the previous version of Power BI and the report is working again. The problem seems to be in the data that's coming from an Excel file.