3. In the section labelled “The following types of messages are exempt from junk mail filtering”, check the box in front of Sender of message is in my Contacts.
4. Optionally, check Sender of message is in my Previous Recipients as well.
5. Close the Preferences window.
Add known senders to your Contacts to prevent Mail from filtering their emails out as spam.
Add any sender you want to protect from spam filtering to the Contacts application on your Mac. You can do that easily from an existing email.
1. Open an email from a sender in the Mail app.
2. Highlight the sender’s name or email address at the top of the email by moving your cursor over it
3. Click the arrow that appears at the end of the highlighted name or email address.
4. Select Add to Contacts from the drop-down menu to open the information in the Contacts application.
5. Enter any additional information for the contact and click Done.