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# OSSystemExtensionError.Code.extensionMissingIdentifier

An error code that indicates the extension identifier is missing.

```
case extensionMissingIdentifier
```

## Discussion

Make sure that the value in the `Info.plist` file of your DriverKit extension matches the identifier string you passed to the [`activationRequest(forExtensionWithIdentifier:queue:)`](/documentation/SystemExtensions/OSSystemExtensionRequest/activationRequest(forExtensionWithIdentifier:queue:)) method.

---

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