# IFatalErrorHandler

Package: [Microsoft.Orleans.Runtime](/orleans/docs/api/csharp/microsoft.orleans.runtime/) 10.0.0

[NuGet package](https://www.nuget.org/packages/Microsoft.Orleans.Runtime)

```csharp
public interface IFatalErrorHandler
```

Interface for controlling how fatal errors (such as a silo being declared defunct) are handled.

## Methods

- [IsUnexpected(Exception)](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.ifatalerrorhandler/methods/isunexpected-system-exception-308d8fbf/)
- [OnFatalException(object, string, Exception)](/orleans/docs/api/csharp/microsoft.orleans.runtime/orleans.runtime.ifatalerrorhandler/methods/onfatalexception-object-string-system-exception-c56819d8/)