On Refresh: A table of multiple values was supplied where a single value was expected

[willpage]

I have a report with about 10 tables in. It's been working fine until recently, but now when I refresh the report I get this error for each of the tables:

Failed to save modifications to the server. Error returned: 'A table of multiple values was supplied where a single value was expected. The current operation was cancelled because another operation in the transaction failed. '.

I presume this is because the data source for one of my tables which has a one to many relationship now contains a duplicate value for the column on the "one" side of the relationship, but which one? All tables say the same thing. How can I troubleshoot this withouts tediously going through all the tables in the query editor and looking for duplicates?

[sjs210]

I have the exact same problem for a very large dataset.  @willpage how did you locate where the problem was?

[willpage]

@amitchandak  thanks for your reply. There are no unintended relationships in the data model. I've checked each table that has the primary key in each one to many relationship for duplicates now, but I can't find any.

I'm looking for a way of finding out exactly where the problem is. The error message isn't telling me which table or relatiopnship is the problem, but are there any other ways of finding out like a 3rd party tool or something?

[amitchandak]

@willpage , You have created a one to many relationship in power bi. And the table one side is getting more than one value or have empty value.

This may be because of auto detect relationship. Close this and go to data model view, Remove unnecessary relationships and try to apply changes or load data again.