> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/electron-userland/electron-builder/llms.txt
> Use this file to discover all available pages before exploring further.

# macOS Kernel Extensions

> Learn how to install macOS kernel extensions using electron-builder scripts

Installing macOS kernel extensions with electron-builder can be done using scripts that run during the installation process.

## Configuration

First, configure your app to build a package (`.pkg`) instead of the default `.dmg`:

```json package.json theme={null}
{
  "build": {
    "mac": {
      "target": "pkg"
    }
  }
}
```

## Script Setup

Place your script and the kernel extensions in `build/pkg-scripts`, or [define a custom directory](/configuration/pkg#scripts).

### Requirements

<Check>The script must be called either `preinstall` or `postinstall`</Check>
<Check>Use `#!/bin/sh` as the first line in your script</Check>
<Check>The script must be executable (`chmod +x <filename>`)</Check>

## Example Script

Here's an example `postinstall` script for managing kernel extensions:

```sh build/pkg-scripts/postinstall theme={null}
#!/bin/sh

echo "Unloading and uninstalling old extensions..."
# unload old extensions
sudo kextunload /Library/Extensions/myExt.kext

# delete old extensions
sudo rm -rf /Library/Extensions/myExtension.kext

# install new extensions
echo "Installing and loading new extensions..."
sudo cp -R myExt.kext /Library/Extensions/myExt.kext
sudo kextload /Library/Extensions/myExt.kext/
```

## Making the Script Executable

Before building, ensure your script has execute permissions:

```bash theme={null}
chmod +x build/pkg-scripts/postinstall
```

## Workflow

1. **Unload existing extensions** - Use `kextunload` to unload any old versions
2. **Remove old files** - Delete old extension files from `/Library/Extensions/`
3. **Copy new extensions** - Copy your new `.kext` files to the system directory
4. **Load new extensions** - Use `kextload` to activate the new extensions

## Directory Structure

```
my-app/
├── build/
│   └── pkg-scripts/
│       ├── postinstall          # Your installation script
│       └── myExt.kext/          # Your kernel extension
├── package.json
└── ...
```

## Custom Script Directory

To use a custom directory for your scripts, configure the `scripts` option:

```json theme={null}
{
  "build": {
    "mac": {
      "target": "pkg"
    },
    "pkg": {
      "scripts": "custom/scripts/directory"
    }
  }
}
```

## Related

* [macOS pkg Configuration](/configuration/pkg)
* [macOS Configuration](/configuration/mac)