Variable.Value() returns error 10418 "The variable ... could not be found"

[FireFighter1017]

I have created a variable library in a premium workspace named "Variables_Dataflows".

In this library I have created a variable named "dfFactMroPurchasingDocuments" with value sets for DEV, QA and PROD.

DEV is the active value set for this workspace.

The variable is working fine when used in a data pipeline.

But when I try to use it in a dataflow residing in the smae workspace, either Gen1 or Gen2, it complains that it could not find the variable.

Here's the M code I used:

let
  Source = Variable.Value("$(/**/Variables_Dataflows/dfFactMroPurchasingDocuments)")
in
  Source

I can't figure out what's wrong with this code.

Anyone can tell me?

[FireFighter1017]

ok @tayloramy , that worked !

That explains why the few sources where I could see this code had more examples using Variable.ValueOrDefault().

I also just noticed the big red box telling us why we should use Variable.ValueOrDefault() in your 1st link.

I still have tests to do before I can safely assume this is working as expected.

I'm hoping to be able to replace all parameters for variables and get rid of deployment rules in deployment pipelines.

Am I wrong?

[tayloramy]

Hi @FireFighter1017, 

There's use cases for both deployment pipeline rules and variable libraries, but I typically lean towards using only variable libraries as you are describing. 

If you found this helpful, consider giving some Kudos. If I answered your question or solved your problem, mark this post as the solution. 

[FireFighter1017]

Hi @tayloramy ,

Yeah I guess until Microsoft finally implements variables for both Gen1 Dataflows and Datasets we'll have to continue using deployment rules.

The funny thing is you can't go through CI/CD with Gen 2 Dataflows without using variables.  They aren't supported for deployment rules.

[tayloramy · Accepted solution]

Hi @FireFighter1017 ,

In Dataflow Gen2, the Power Query editor does not resolve Variable Library values at design time, so Variable.Value("$(/**/Library/Variable)") often throws 10418 in the editor even when the variable exists. Variables are resolved at run time. Also, Variable Libraries are only supported in Dataflow Gen2 with CI/CD, not in Dataflow Gen1. See Microsoft’s docs and notes here: Use Fabric variable libraries in Dataflow Gen2 (Preview).

 

• Use Dataflow Gen2 with CI/CD (not Gen1) and keep the Variable Library in the same workspace as the dataflow. Docs
• During authoring, call Variable.ValueOrDefault so the editor can evaluate a fallback; at refresh time Fabric will use the real variable value. Docs
• Make sure your identifier matches this exact format (display names, including spaces):
  $(/**/LibraryName/VariableName)
• Test by running the dataflow (Publish + Refresh). Don’t rely on the editor preview for variables. Docs

Example M you can drop in

// Works in authoring (fallback) and resolves at run time
let
  TableName =
    Variable.ValueOrDefault(
      "$(/* */*/Variables_Dataflows/dfFactMroPurchasingDocuments)",
      "dfFactMroPurchasingDocuments_DevFallback"   // match the variable's data type
    ),
  Source = SomeConnectorFunction( TableName )
in
  Source

If you found this helpful, consider giving some Kudos. If I answered your question or solved your problem, mark this post as the solution.

[anilgavhane]

Check Variable Scope

• Ensure the variable is published and accessible to Dataflows.
• Confirm that the active value set (DEV) is correctly assigned to the workspace.

2. Use Correct Syntax

Try simplifying the path:

Source = Variable.Value("Variables_Dataflows/dfFactMroPurchasingDocuments")

Or even:

Source = Variable.Value("dfFactMroPurchasingDocuments")

Sometimes the full path with $(/**/) is not required in Dataflows.

3. Test with a Static Value

To isolate the issue, replace the variable call with a hardcoded value:

Source = "DEV"

If this works, the issue is with variable resolution—not the rest of your query.

 4. Check Dataflow Type

• Gen1 Dataflows have limited support for advanced features.
• Gen2 Dataflows are more flexible but still evolving.
• Try recreating the Dataflow in Gen2 and reapplying the variable.

 5. Use Parameters Instead

If variables fail, consider using Dataflow Parameters as a workaround:

• Define a parameter in the Dataflow UI.
• Reference it in your M code:

Source = ParameterName

 Known Limitations

According to recent community feedback and Microsoft documentation:

• Variable.Value() is not yet fully supported in Dataflows, even in Premium workspaces.
• It works in Data Pipelines, but not consistently in Dataflows, especially when referencing external libraries.

 Recommendation

Until full support is rolled out:

• Use parameters in Dataflows.
• Keep using variables in Pipelines.
• Monitor Microsoft Fabric updates for expanded support.

[FireFighter1017]

Hi @anilgavhane ,

The purpose of this is to specificaly stop using parameters in dataset and dataflows that need to reference existing dataflows.  Mainly because it is a PIA to maintain in deployment pipeline rules.

We are starting to use data pipelines and using variable libraries seems like an obvious choice for future developments.