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Medium severitydata source

Power BI Refresh Error:
AzureBlobInvalidBlockSize

What does this error mean?

The block size specified for the Azure Blob Storage write operation is invalid. Azure Blob Storage has minimum and maximum constraints on block size for block blobs.

Common causes

  • 1The block size value in the copy activity sink settings exceeds the maximum allowed per-block size
  • 2The block size is set to zero or a negative value
  • 3An incorrect formula or expression resolved to an invalid block size at runtime

How to fix it

  1. 1Review the block size setting in the copy activity sink dataset or linked service for Azure Blob Storage.
  2. 2Ensure the block size is within the valid Azure Blob Storage range (4 MB minimum, 100 MB maximum per block).
  3. 3Remove the custom block size setting to use the ADF default, which is within valid bounds.

Frequently asked questions

Does this error affect all pipeline runs or just the current one?

Depends on the root cause. A persistent misconfiguration fails every run; a transient issue may resolve on retry. Check the run history.

Can this error appear in Azure Data Factory and Microsoft Fabric pipelines?

Yes — the same connector errors appear in both ADF and Fabric Data Factory pipelines.

How do I see the full error detail for an ADF pipeline failure?

In ADF Monitor, click the failed run, then the failed activity. The detail pane shows the error code, message, and sub-error codes.

Will downstream Power BI datasets be affected when an ADF pipeline fails?

Yes — a dataset refreshing after the pipeline will use stale data or fail if the target table was cleared. The Power BI refresh may succeed while serving wrong data.

Official documentation: https://learn.microsoft.com/en-us/azure/data-factory/connector-troubleshoot-azure-blob-storage

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