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# systemFreeSize

The key in a file system attribute dictionary whose value indicates the amount of free space on the file system.

```
static let systemFreeSize: FileAttributeKey
```

## Discussion

The corresponding value is an [`NSNumber`](/documentation/Foundation/NSNumber) object that specifies the amount of free space on the file system in bytes. The value is determined by `statfs()`.

> Important:
> This API has the potential of being misused to access device signals to try to identify the device or user, also known as fingerprinting. Regardless of whether a user gives your app permission to track, fingerprinting is not allowed. When you use this API in your app or third-party SDK (an SDK not provided by Apple), declare your usage and the reason for using the API in your app or third-party SDK’s `PrivacyInfo.xcprivacy` file. For more information, including the list of valid reasons for using the API, see <doc://com.apple.documentation/documentation/BundleResources/describing-use-of-required-reason-api>.

---

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