macOS Sonoma: BusyContacts Mail Plug-in Not Allowed

If Apple Mail reports that the old BusyContacts plug-in is incompatible or cannot be enabled after upgrading to macOS Sonoma or later, use BusyContacts Mail Assistant, the current Apple Mail extension.

Use the Mail extension

With a current BusyContacts release installed, follow Adding Mail. It explains how to enable capture in BusyContacts and turn on BusyContacts Mail Assistant in Mail > Settings > Extensions.

The extension captures matching messages as Apple Mail makes them available. It cannot automatically import your entire mail history; open older messages in Apple Mail to make them available for capture.

About the old plug-in

The legacy Apple Mail plug-in is no longer supported. Reinstalling it, enabling Manage Plug-ins, or changing macOS security settings does not provide the current Mail Assistant integration.