What causes UserErrorTypeConversionFailure?

A source string column contains non-numeric values being cast to an integer or decimal target column. A date string in the source does not match the expected format and cannot be parsed to a datetime. A source value exceeds the precision or scale of the target numeric column. Null values in the source are being written to a NOT NULL target column

How do I fix UserErrorTypeConversionFailure?

Enable fault tolerance in the copy activity to skip incompatible rows: Copy activity > Settings > Fault tolerance > Skip incompatible rows.. Check the fault tolerance log path to identify which specific rows caused the conversion failure.. Fix the source data, or add a data flow transformation to cast or clean the data before writing to the target.. Update the target column data type if it is too restrictive for the actual data range.. Use a staging table or a pre-copy script to validate and transform data before writing to the final destination.

Medium severitydata source

Power BI Refresh Error:
UserErrorTypeConversionFailure

What does this error mean?

An Azure Data Factory copy activity failed because a value from the source cannot be converted to the target column's data type. Specific rows contain values that are incompatible with the sink schema.

Common causes

1A source string column contains non-numeric values being cast to an integer or decimal target column
2A date string in the source does not match the expected format and cannot be parsed to a datetime
3A source value exceeds the precision or scale of the target numeric column
4Null values in the source are being written to a NOT NULL target column

How to fix it

1Enable fault tolerance in the copy activity to skip incompatible rows: Copy activity > Settings > Fault tolerance > Skip incompatible rows.
2Check the fault tolerance log path to identify which specific rows caused the conversion failure.
3Fix the source data, or add a data flow transformation to cast or clean the data before writing to the target.
4Update the target column data type if it is too restrictive for the actual data range.
5Use a staging table or a pre-copy script to validate and transform data before writing to the final destination.

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/copy-activity-fault-tolerance