Fabric: Issues with default semantic model / "an item with same key.." error

[Andrey_Hamburg]

Hello dear community,

I have one project where we create real reporting system for a D365 F&O environment usng "Fabric". We export data from "F&O" to a lakehouse, then I created several views to build a star schema and those views were exposed as "default semantic model" to PowerBI users.

2 days ago I started to experience issues with the model: I could not add new tables, I could not change properties of columns. And everything ended with getting permanently this error:

I deleted all my custom views - nothing changed. 

Searching in Internet on PowerBI forums brought me to information, that this error might be caused by duplicate column names. But I actually removed all custom views which could have equally named columns (and columns with same name in D365-tables were not an issue in the past).

At the end I had to reset my environment completely - unlink in dataverse and relink again. Can anyone perhaps give me a hint, what this error mmeans and how I can avoid it in the future?

Best regards from Hamburg,

Andrey

[Anonymous]

Hi @Andrey_Hamburg ,

As you have discovered, duplicate column names in the semantic model do cause problems. The following are some suggestions for troubleshooting and possibly resolving the issue:

1. Use Power BI Desktop or Power BI Services to take a closer look at all tables and columns in the semantic model for duplicate entries. Therefore, "ColumnA" and "columna" will be treated as duplicates.
2. Ensure that the semantic model does not have tables or PowerQuery M expressions with the same name. This is a common problem that can lead to errors, as Power BI does not allow such duplicates. If found, rename the expression or table as needed.
3. Hidden characters or spaces in column names may immediately display problems. Use the TRIM function in Power Query to clean up the column names and remove any leading or trailing spaces.

If the above suggestions do not help you, could you provide some details:

• Is the error something that happens suddenly, making it an intermittent or persistent error.
• Did you do anything else before the error occurred.

Best Regards,

Ada Wang

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

[Jonvoge]

Hi Audrey_Hamburg

Is it possible for you to create a New Semantic Model from the Reporting tab in your Lakehouse SQL Endpoint?

And if so, do you experience the same issue there?

I've seen a couple of weird bugs with adding/removing tables to the deafult semantic model, and find the ones I create myself to be much more stable.

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[Andrey_Hamburg]

Hello Jonvoge,

thanks for the hint. I also was thinking about creating custom semantic model, but first I have to make the whole system running again.

I cannot really understand what exactly brought my default model to that error "an item with the same key...". Knowing it would prevent me from repeating the same mistake again.

Kind regards,

Andrey