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Power BI Refresh Error:
DF-Executor-ExpressionParseError

What does this error mean?

An expression in a data flow transformation — a Derived Column, filter, join condition, or aggregate — contains a syntax error that the ADF expression engine cannot parse. The pipeline fails immediately at runtime before any data is processed.

Common causes

  • 1A string literal in an expression uses double quotes instead of single quotes — ADF's expression language requires single-quoted string literals
  • 2A parameter reference uses `@{pipeline().parameters.name}` syntax (ARM template style) instead of the data flow expression syntax `$paramName`
  • 3An expression was edited directly in JSON or copied from another tool, introducing invisible characters or encoding issues that break parsing
  • 4A function name is misspelled or used with the wrong number of arguments — ADF expression functions are case-sensitive

How to fix it

  1. 1Open the ADF data flow expression builder for the failing transformation and check for syntax errors — look for unclosed parentheses, mismatched quotes, or invalid function names.
  2. 2The error message names the line or expression that failed to parse; navigate directly to that Derived Column or filter expression.
  3. 3Validate each function call in the expression against the ADF expression language reference — function names are case-sensitive.
  4. 4If the expression includes pipeline parameters, verify the parameter syntax: use `$paramName` not `@paramName` in data flow expressions.
  5. 5Use the expression builder's 'Refresh' button to re-evaluate the expression and see the parse error highlighted in context.

Frequently asked questions

The expression looks correct to me — why is it still failing to parse?

Most common hidden cause: ADF expressions require single-quoted string literals, not double quotes. Also check parameter syntax — use `$paramName` in data flow expressions, not `@pipeline().parameters.paramName`. Use the Refresh button to see the highlighted parse error.

Can I copy expressions from one data flow to another?

Yes — copy through the ADF expression builder interface, not JSON. JSON-level copying can introduce encoding issues or miss context-specific column references that exist in one data flow but not another.

Does ExpressionParseError ever occur only on some runs?

No — a parse failure occurs on every run. Inconsistent failures suggest a different error code.

The error says 'line 1, column 47' — how do I find that position in a complex expression?

Open the expression builder for the named transformation and paste the expression. The builder highlights syntax errors inline. The line/column position in the error message refers to the expression text, not the pipeline JSON.

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

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