The latest version of Mailbutler is compatible with macOS 10.12 Sierra or later. For macOS 10.11 El Capitan, please download and install the following Mailbutler version:
After the download, follow the Apple Mail plugin installation process described below.
1. Open your Downloads folder and double click on the zip file.
2. Double click on the Mailbutler installer file to open.
3. Confirm the installation by clicking Open.
4. Click the button to move Mailbutler into your Applications Folder.
5. If requested, click OK to give permission to install Mailbutler.
6. Follow the on-screen instructions to complete the installation.
7. Once the installation is complete, restart Apple Mail.
8. Go to your menu bar and click on the Mailbutler icon to open your companion app. Login to your account to activate the plugin.