Main.xaml language 'VisualBasic' is incompatible with project's language 'CSharp'. This configuration is not supported

I created a few processes and they were all running fine both from Studio and Orchestrator.
Few days ago we reinstalled studio from User Mode to Service Mode as recommeded by UiPath support team.
Now when I open Studio in each process in Output panel I get this error message:
Main.xaml language ‘VisualBasic’ is incompatible with project’s language ‘CSharp’. This configuration is not supported.
But process is still working fine from both Studio and Orchestrator. Do you know why this error is coming up and will we face any issues in future if this is not resolved?

Thank you,
Marijana Martinac

Studio version: 2022.4.5

1 Like

HI @Marijana

Have you checked this thread?


Try this possible solution:

  1. Open the .xaml in Studio (double click on the .xaml file).

  2. Close the UiPath Studio application.

  3. Open the generated project.json file and look for

"expressionLanguage": "CSharp"

and replace it with

"expressionLanguage": "VisualBasic"
  1. Save the project.json file and close it.

  2. Reopen the .xaml file in UiPath Studio.

Let us know if you still have the error after performing the above.

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I tried it and I no longer see the error message in Studio, but when I tried to run the process from Studio I got a new one:
Click ‘Close’: Expression Activity type ‘CSharpValue`1’ requires compilation in order to run. Please ensure that the workflow has been compiled.

Which is the default language in your Studio? (C# or VB .net)

Rebuild the Click Close activity in your project.

1 Like

I did, now all is working fine since that was the only activity causing problems. Thank you

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