With this option enabled, SpamSieve will never predict a message to be spam if its sender’s e-mail address is in the Contacts (previously Address Book) application.
You can add addresses to the system address book using the Contacts or Address Book application (located in the /Applications folder), or directly from an e-mail program that supports the system address book.
If spam messages get through to your inbox because they are sent from addresses in your address book, you can either uncheck Use macOS Contacts or see the Catch spam sent from my own addresses section.
The Granting Contacts Access section explains how you can make sure that SpamSieve has access to read the macOS Contacts database.
Mail Client Contacts
Outlook and Entourage users may prefer to use Microsoft’s address book as an allowlist instead of Apple’s. This is described in the Use Outlook/Entourage contacts section.
PowerMail users should be sure to enable the option to use Apple’s address book.