Editing a Large Semantic Model (LSM) Dataset with Incremental Refresh in Power BI Service

Hello msam1977_SM ,

Question 1 :

No, it is not possible to temporarily disable the large storage format directly from the Power BI service. Once a model is published with this format and incremental refresh enabled, downloading the PBIX file is disabled for performance and data security reasons.

The only way to retrieve an editable file is to work from the original PBIX file used for publishing. If you no longer have it, you will need to rebuild the model manually or use tools such as Tabular Editor to make changes directly to the model in the service.

Question 2 :

Yes, republishing a local PBIX file will overwrite the existing dataset in the Power BI service. This includes:

• The model structure
• Incremental refresh settings
• Relationships and measures
• Data that has already been loaded

This may disrupt existing reports that depend on this dataset, especially if fields or tables are modified or deleted.

Question 3 :

• Use Tabular Editor : Tabular Editor allows you to edit the model directly in the Power BI service via XMLA endpoint. You can edit measures, calculated columns, DAX expressions, and even some table properties.
  This avoids republishing the PBIX file and preserves existing data and reports.
  
  
• Work on a local copy :  If you have a copy of the original PBIX file: Make the changes locally, publish to a test workspace, check that everything works (refresh, reports, etc.) and then publish to the production workspace outside of critical hours.
  
  
• Use dynamic parameters and sources : For JSON data, consider pre-processing the data in Power Query or via an external pipeline (Azure Data Factory, Fabric, etc.).This keeps the model simpler and avoids frequent changes.

Don't hesitate to give a kudo and validate as a solution if my answer helped you.

Have a nice day,

Vivien