# Octopus Script Step Error: "Common Language Runtime detected an invalid program"


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You might run into the following error when deploying with Octopus and one of your tasks is executing a C# script (ScriptCS) on the target machine.
 
![octopus script error](https://cdn.hashnode.com/res/hashnode/image/upload/v1653484106750/SdUgfLq2n5.png)

```
ERROR: Script execution failed. [InvalidProgramException] Common Language Runtime detected an invalid program.
Exit code: 1
The remote script failed with exit code 1
```
 
This is most likely because .NET 4.5.2 is not installed on the machine. If you install that the error should go away.
 
There's a bit more info available on the following links:
 
- https://github.com/dotnet/corefx/issues/320
- https://github.com/dotnet/corefx/pull/687

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