How to Filter Unknown Senders on macOS 13 Mail

While macOS 13 (Ventura) does not include a single one-click toggle to filter unknown senders in the Mail app, you can easily filter them by creating a custom Mail Rule or using a Smart Mailbox. By setting conditions based on your Contacts list, you can automatically divert messages from unfamiliar senders to a dedicated folder or create a focused inbox that only displays emails from people you know.

Method 1: Create a Rule to Move Unknown Senders

Setting up a rule allows Mail to automatically route incoming messages from senders not in your address book into a separate folder.

  1. Create a Destination Folder:
    • Open the Mail app on your Mac.
    • Go to the menu bar, select Mailbox > New Mailbox.
    • Name the mailbox (e.g., "Unknown Senders") and choose where to store it (such as "On My Mac" or within your specific email account). Click OK.
  2. Set Up the Rule:
    • In the top menu, click Mail > Settings (or press Command + ,).
    • Select the Rules tab.
    • Click the Add Rule button.
    • In the Description field, enter a name like Filter Unknown Senders.
    • Under the condition dropdowns, configure the rule to read:
      • Sender is not in my contacts
    • (Optional) Click the + (plus) icon to add a second condition: Sender is not in my previous recipients.
    • Under Perform the following actions, set the action to:
      • Move Message to mailbox: Unknown Senders.
    • Click OK to save the rule.
    • When prompted to apply the rule to existing messages, select Apply if you want to sort current emails, or Don't Apply to sort only future incoming messages.

Method 2: Create a Smart Mailbox for Known Contacts Only

If you prefer not to move messages automatically but want an inbox view free of unfamiliar senders, you can create a Smart Mailbox.

  1. Open Mail, click Mailbox in the menu bar, and select New Smart Mailbox.
  2. Name the mailbox (e.g., "Known Contacts").
  3. Set the condition to: Sender is in my contacts.
  4. Click OK.

This creates a virtual folder in your sidebar that aggregates messages exclusively from your saved contacts without altering their actual location on the server.

Method 3: Adjust Junk Mail Exemptions

You can also use macOS 13's built-in Junk Mail filters to ensure unknown senders undergo stricter filtering:

  1. Open Mail > Settings > Junk Mail.
  2. Ensure Enable junk mail filtering is checked.
  3. Under the exemptions list, check the box for Sender of message is in my Contacts.
  4. Check the box for Sender of message is in my Previous Recipients.

Any email arriving from an address not matching these lists will be scrutinized more aggressively by the spam filter and moved to your Junk folder if flagged.