Since macOS Mojave (10.14), it is now required to activate Apple Mail plugins before using them. To start using your inbox with Mailbutler, you’ll need to first enable Mailbutler.mailbutler manually through your Apple Mail Preferences and restart Mail.
Activate Mailbutler plugin on Apple Mail
- Open Apple Mail.
- Click Mail in the menu bar on the top left of your screen.
- Click Preferences…
- Click on Manage Plug-ins in the General tab.
- Activate the plugin Mailbutler.mailbundle by checking the checkbox.
- Click Apply and Restart Mail.
- Open Apple Mail and start using Mailbutler. You should now see Mailbutler icons and features within your email client.