---
title: layerUUID
framework: diskimagekit
role: symbol
role_heading: Instance Property
path: diskimagekit/diskimage/layeruuid
---

# layerUUID

A UUID of the image that the framework uses to validate its compatibility with the layer above it in the stack

## Declaration

```swift
var layerUUID: UUID? { get }
```

## Discussion

Discussion All images contain a layer UUID, except for RAW images. The layer UUID changes when the framework first writes to an image. In a stacked disk image, the framework can only write to the topmost image. The layer UUID of cache layers never changes.