# OnPreprocessBuild(BuildReport)

> Implement this method to receive a callback before the build is started.

## Definition

* **Type:** Method
* **Namespace:** [UnityEditor.Build](/engine/6000.7/script-reference/unityeditor/build.md)
* **Assembly:** UnityEditor.CoreModule

```csharp
void OnPreprocessBuild(BuildReport report)
```

### Parameters

**** (\[BuildReport]\(/engine/6000.7/script-reference/unityeditor/build/reporting/buildreport)): A report containing information about the build, such as its target platform and output path.

### Remarks

This method is invoked during Player builds only. Use [IPreprocessBuildWithContext.OnPreprocessBuild](/engine/6000.7/script-reference/unityeditor/build/ipreprocessbuildwithcontext/onpreprocessbuild.md) instead, which is also invoked during AssetBundle and content directory builds.

Additional Resources: [IPostprocessBuildWithReport](/engine/6000.7/script-reference/unityeditor/build/ipostprocessbuildwithreport.md), [BuildPlayerProcessor](/engine/6000.7/script-reference/unityeditor/build/buildplayerprocessor.md), [BuildPipeline.BuildPlayer](/engine/6000.7/script-reference/unityeditor/buildpipeline/buildplayer.md)