---
title: PreviewUnavailable
framework: developertoolssupport
role: symbol
role_heading: Structure
path: developertoolssupport/previewunavailable
---

# PreviewUnavailable

An error that the system throws when a preview is unavailable at runtime.

## Declaration

```swift
struct PreviewUnavailable
```

## Overview

Overview This type supports the expansion of preview macros. You don’t use it directly.

## Topics

### Creating an instance

- [init()](developertoolssupport/previewunavailable/init().md)

## Relationships

### Conforms To

- [Error](swift/error.md)
- [Sendable](swift/sendable.md)
- [SendableMetatype](swift/sendablemetatype.md)