Calculation group issue PBIRS

[NiklasR]

So we recently updated our report server and desktop setup to January 2025 version and with it came a great bunch of new functionalities! 
As I was trying out the calculation groups functionally, I learned the hard way that it is not quite ready yet. If you have a model which is using direct query, then add a calculation group. The group automatically has storage mode "import", which makes the model a composite model. Which as far as I have understood is not supported for pbi report server(yet). So when I saved my report to the server, closed desktop and the next day tried to reopen my report I got the error message that my file is using a composite model and it's not supported in pbi report server. So I couldn't open it anymore, meaning I couldn't remove the calculation group. Meaning I had to grab an older version of my report and copy that data model into my new one and redo all of my work. I also tried opening it locally but it's the desktop version that doesn't support the model so that didn't help either. I don't have the option to open the report in a "regular" pbi desktop to fix it either.

I think maybe the calculation groups option shouldn't be accessible if it basically breaks your dataset(with import data) if you are using direct query.

I am not sure if this is a "bug" or if I as a user/developer should know about this but it seems to me like maybe the calculation groups setting should either be turned off or at least warn if you have a model using direct query storage mode.

@Petebro

Let me know if there are any more specifications you need from me, but I assume this is a general thing. 

TLDR: PBI Report server + Direct query storage mode + adding calculation group = Bad

[NiklasR]

Thank you both for your answers @johnbasha33 and @rohit1991, I felt slightly better knowing I am not alone in this. I guess there won't be a "solution" to this thread until something is changed in the upcoming PBIRS versions (like support for composite models). So I guess I can close it for now.

Thanks! 

[rohit1991 · Accepted solution]

Hi @NiklasR ,

You're absolutely right to be frustrated—what you've encountered is a known limitation rather than a bug, and unfortunately it's not well-communicated within Power BI Report Server (PBIRS) tooling. Calculation groups are a powerful feature introduced in recent updates, but they rely on a model capability (composite models with mixed storage modes) that PBIRS does not yet support. Once you add a calculation group, it implicitly switches your model to a composite one (since calculation groups require Import mode), which makes it incompatible with the current PBIRS engine—even though the UI allows you to add them without any warning. This leads to the very problem you experienced: the file becomes unreadable in PBIRS and Power BI Desktop RS, effectively locking you out of your own report.

Ideally, the UI should restrict or at least warn users when they attempt to add features like calculation groups in a DirectQuery-only model targeted for PBIRS, but as of now, this safeguard doesn't exist. Until Microsoft addresses this gap, the best workaround is to either avoid using calculation groups in PBIRS-bound reports or maintain version-controlled backups of your .pbix files before enabling new features. This way, you can recover quickly without losing significant development work. You're not alone in this—hopefully this gets addressed in a future update with either support for composite models in PBIRS or proper user guidance.

Passionate about leveraging data analytics to drive strategic decision-making and foster business growth.

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[johnbasha33]

Hi @NiklasR 

It seems like you're encountering a known issue with Power BI Report Server and DirectQuery models when using calculation groups. Since calculation groups are stored in "import" mode by default, it conflicts with DirectQuery, which can cause the model to be treated as a composite model, unsupported by the report server.

As of now, this limitation seems to stem from the interaction between DirectQuery and calculation groups, and it's something users need to be cautious of. The suggestion you mentioned about adding a warning or disabling the option to use calculation groups when DirectQuery is involved would indeed be a helpful feature to prevent this issue from occurring in the future.

For now, it would be best to avoid adding calculation groups to DirectQuery models on Power BI Report Server or use a workaround like reverting to an older version of the report, as you did. You might also want to keep an eye on updates from Microsoft that could address this limitation in future releases.

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