---
title: NEURLFilterManager.Error.extensionNotFound
framework: networkextension
role: symbol
role_heading: Case
path: networkextension/neurlfiltermanager/error/extensionnotfound
---

# NEURLFilterManager.Error.extensionNotFound

The system can’t find the app extension.

## Declaration

```swift
case extensionNotFound
```

## See Also

### Extension errors

- [NEURLFilterManager.Error.extensionCancelled](networkextension/neurlfiltermanager/error/extensioncancelled.md)
- [NEURLFilterManager.Error.extensionFailedToLoad](networkextension/neurlfiltermanager/error/extensionfailedtoload.md)