What causes Fabric Pipeline Error 4101?

A required property on the AzureMLExecutePipeline activity (such as `mlPipelineId` or `experimentName`) has an incorrect format, wrong type, or empty value. Dynamic expressions or parameter references used in the activity property resolve to null or an unexpected value at runtime. The activity JSON was manually authored or migrated and contains a typo or incorrect data type for the flagged property. A referenced Azure ML pipeline ID was changed or deleted, making the stored value invalid

How do I fix Fabric Pipeline Error 4101?

Step 1: Review the full pipeline run error message to identify which specific `%activityName;` and `%propertyName;` are flagged as invalid.. Step 2: Open the identified AzureMLExecutePipeline activity in the pipeline editor and navigate to the settings for the flagged property.. Step 3: Verify that the property value matches the expected format — for example, confirm that `mlPipelineId` is a valid GUID corresponding to an existing published Azure ML pipeline.. Step 4: If dynamic expressions are used, test the expression output using the pipeline expression builder to confirm it resolves to a valid non-null value.. Step 5: Save the corrected activity definition, validate the pipeline, and trigger a new run to confirm the error is resolved.

High severityconfigurationMicrosoft Fabric →

Power BI Refresh Error:
Fabric Pipeline Error 4101

What does this error mean?

An `AzureMLExecutePipeline` activity contains an invalid value or missing definition for one of its required properties. The pipeline cannot submit the Azure Machine Learning pipeline run until the property is corrected.

Common causes

1A required property on the AzureMLExecutePipeline activity (such as `mlPipelineId` or `experimentName`) has an incorrect format, wrong type, or empty value
2Dynamic expressions or parameter references used in the activity property resolve to null or an unexpected value at runtime
3The activity JSON was manually authored or migrated and contains a typo or incorrect data type for the flagged property
4A referenced Azure ML pipeline ID was changed or deleted, making the stored value invalid

How to fix it

1Step 1: Review the full pipeline run error message to identify which specific `%activityName;` and `%propertyName;` are flagged as invalid.
2Step 2: Open the identified AzureMLExecutePipeline activity in the pipeline editor and navigate to the settings for the flagged property.
3Step 3: Verify that the property value matches the expected format — for example, confirm that `mlPipelineId` is a valid GUID corresponding to an existing published Azure ML pipeline.
4Step 4: If dynamic expressions are used, test the expression output using the pipeline expression builder to confirm it resolves to a valid non-null value.
5Step 5: Save the corrected activity definition, validate the pipeline, and trigger a new run to confirm the error is resolved.

Frequently asked questions

How do I find the correct value for `mlPipelineId` to use in an AzureMLExecutePipeline activity?

Navigate to Azure Machine Learning Studio, go to Pipelines > Published Pipelines, and copy the pipeline ID from the details page of the published pipeline you want to invoke.

Can pipeline parameters cause Error 4101 if they pass wrong values at runtime?

Yes — if a pipeline parameter used in an AzureMLExecutePipeline property resolves to an incorrect type or null at runtime, Error 4101 will be raised even if the static JSON definition appears correct. Always validate dynamic expressions before deploying to production.