# GrainExtensionNotInstalledException

Package: [Microsoft.Orleans.Core.Abstractions](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/) 10.0.0

[NuGet package](https://www.nuget.org/packages/Microsoft.Orleans.Core.Abstractions) | [Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Orleans.Core.Abstractions/Exceptions/GrainExtensionNotInstalledException.cs#L11)

```csharp
[Orleans.GenerateSerializer]
public sealed class GrainExtensionNotInstalledException : OrleansException
```

Signifies that an attempt was made to invoke a grain extension method on a grain where that extension was not installed.

## Constructors

- [GrainExtensionNotInstalledException](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/orleans.runtime.grainextensionnotinstalledexception/constructors/constructor-7a939711/)
- [GrainExtensionNotInstalledException(string)](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/orleans.runtime.grainextensionnotinstalledexception/constructors/constructor-string-11f9e5a3/)
- [GrainExtensionNotInstalledException(string, Exception)](/orleans/docs/api/csharp/microsoft.orleans.core.abstractions/orleans.runtime.grainextensionnotinstalledexception/constructors/constructor-string-system-exception-bdd21029/)