What causes DF-Blob-FunctionNotSupport?

The data flow sink is configured to use folder-level operations or atomic rename that require ADLS Gen2 hierarchical namespace, but the target account is a standard Blob Storage account without hierarchical namespace enabled. A Delta Lake sink is pointed at a standard Blob Storage account — Delta Lake requires ADLS Gen2 or equivalent filesystem semantics. The data flow is attempting to read folder-partitioned data using a function that is only supported on ADLS Gen2

How do I fix DF-Blob-FunctionNotSupport?

Check the target storage account in the Azure portal — confirm whether hierarchical namespace (HNS) is enabled under 'Configuration'.. If your use case requires Delta Lake, folder atomics, or directory-level operations, migrate the target to an ADLS Gen2 account (hierarchical namespace enabled).. If you must use standard Blob Storage, change the sink format to one that does not require filesystem-level operations (e.g., CSV or Parquet with file-level writes only).. Review the ADF activity run output for the specific sub-error to confirm which function triggered the failure.

Medium severitydata source

Power BI Refresh Error:
DF-Blob-FunctionNotSupport

What does this error mean?

The ADF Mapping Data Flow Azure Blob Storage connector attempted a function or operation that the Blob Storage service does not support.

Common causes

1The data flow sink is configured to use folder-level operations or atomic rename that require ADLS Gen2 hierarchical namespace, but the target account is a standard Blob Storage account without hierarchical namespace enabled
2A Delta Lake sink is pointed at a standard Blob Storage account — Delta Lake requires ADLS Gen2 or equivalent filesystem semantics
3The data flow is attempting to read folder-partitioned data using a function that is only supported on ADLS Gen2

How to fix it

1Check the target storage account in the Azure portal — confirm whether hierarchical namespace (HNS) is enabled under 'Configuration'.
2If your use case requires Delta Lake, folder atomics, or directory-level operations, migrate the target to an ADLS Gen2 account (hierarchical namespace enabled).
3If you must use standard Blob Storage, change the sink format to one that does not require filesystem-level operations (e.g., CSV or Parquet with file-level writes only).
4Review the ADF activity run output for the specific sub-error to confirm which function triggered the failure.

Frequently asked questions

What is the difference between Azure Blob Storage and ADLS Gen2?

ADLS Gen2 is Blob Storage with hierarchical namespace enabled, unlocking POSIX-like directory operations (atomic rename, directory delete) that Mapping Data Flows and Delta Lake require for consistent writes.

Can I enable hierarchical namespace on an existing Blob Storage account?

No — hierarchical namespace can only be enabled at account creation. To migrate, create a new ADLS Gen2 account and copy the existing data using ADF or Azure Storage Explorer.

Does this error mean my Blob Storage linked service credentials are wrong?

No — this error is about unsupported functionality, not authentication. If the connection test passes, credentials are fine — the issue is the operation type.

Official documentation: https://learn.microsoft.com/en-us/azure/data-factory/data-flow-troubleshoot-guide