Question on December 2020 Update - Please respond

Anonymous 

That's a pretty obvious problem: your refresh is trying to add a row with a value that matches an existing value but the column is marked as being unique, that would changes the exiting model relationship. Please check the datasource and pbi model see what value it complains about, and why it is adding a duplicate to the current model.

Regarding to version updates, you should always update both Report Server and Desktop for RS to the newest version to able to prevent potential errors caused by feature updates. Just in stall the newest version Dec 2020, no need update to Nov then Dec.

Paul Zheng _ Community Support Team
If this post helps, please Accept it as the solution to help the other members find it more quickly.