A new contact's first text or email may skip your inbox. Where to look

You swap details with someone at a conference on Tuesday. On Wednesday morning they text from a work phone you never saved, and that afternoon they email from the address you did save. On an iPhone with unknown-sender screening turned on, the text can wait in a separate Unknown Senders list, possibly without a notification. The email can land under Updates in Apple Mail, or outside Gmail's Primary tab, where Gmail sends no new-mail alert. Nothing is lost, and each filter can be taught in one step. [1] [2] [3]

The short version: save the person with the exact number and address they will use before you part, check the filtered folders for a day or two, and when their first message turns up in one, use the action that teaches the filter. On iPhone, replying is not that action.

The people, numbers and addresses in this guide are fictional. Steps are labelled with the version of iOS or macOS whose Apple documentation we checked on 30 September 2026.

What Apple counts as "known"

On iPhone, Apple defines an unknown sender as "anyone you haven't previously interacted with in Messages or someone who isn't in your contacts." [1] The macOS Tahoe 26 guide puts it from the other side: a known sender "can be someone you've marked as known or added to the Contacts app." [4] Apple's Mac and iPhone guides add that until you do one of those two things, any future messages from that sender go to Unknown Senders too. [4] [5] [6]

Replies work differently from what many people expect. Apple's iOS 26 article says that replying to an unknown sender "does not automatically mark the sender as known" or move the conversation into your list. [1] The same article says message filtering doesn't apply to a sender you've replied to three times or more, so a real back-and-forth eventually lifts the filter. [1] The iOS 27 guide repeats that rule only for its separate text-message filter, and the Mac guides don't mention it. [6]

Content is held back as well. The macOS 27 and iOS 27 guides say you can open links and see blurred images from an unknown sender once you mark them known or add them to Contacts, and the Tahoe 26 guide gives a link you can't open as a reason to do so. [5] [6] [4]

Is screening on?

Apple documents one default. In iOS 26, Screen Unknown Senders is off unless you had Filter Unknown Senders turned on in iOS 18, in which case it is on after the upgrade. [1] The iOS 27 guide, and the Mac guides for Tahoe 26 and macOS 27, describe how to turn screening on but don't state the default. [6] [4] [5] Apple's "What's new" page for Messages in macOS 27 says unknown senders "get filtered from your conversation list", while the setup steps still ask you to select "Screen unknown senders". [7] [5] Rather than guess, open the setting on each device you use.

Spam is a separate filter, and here the defaults are documented. Filter Spam is on by default in iOS 26 and later, and you get no notification for messages it catches. [8] On the Mac, Apple's macOS 27 guide says spam filtering is on by default. [9]

Where a first contact can land

This table brings together the Apple and Google pages cited below it. It is our synthesis, not a table either company publishes. "Not stated" means we checked the page and it doesn't say.

[1] [6] [5] [4] [8] [9] [10] [2] [3]

Which unknown senders still reach you

On iPhone, Time Sensitive notifications from unknown senders, such as verification codes, are on by default. In Settings > Apps > Messages > Unknown Senders > Allow Notifications you can switch four categories on or off: Time Sensitive, Personal, Transactions and Promotions. [1] Where you live changes what that screen offers. Apple says that in most countries and regions unknown senders notify by default, and that the United States, Brazil and India let you choose which categories notify. [1] Apple doesn't document how it decides that a given text is Personal, so allowing that category improves your odds without guaranteeing an alert.

An allowed notification is also temporary. Messages from unknown senders that you allowed to notify stay in your conversation list for eight hours, then move to Unknown Senders. [1] If you glanced at a message from an unfamiliar number and didn't act on it, look for it later in Unknown Senders.

Email and calls

Apple Mail on the Mac sorts mail into Primary, Transactions, Updates and Promotions where the feature is available. Apple's note that a message in the other categories is also shown in Primary when it "includes time-sensitive information" is useful, but it is no promise that a first email from a new person will be treated that way. Control-click a message and choose Categorize Sender to move all of that sender's current and future messages to the category you choose. The macOS Tahoe 26 and macOS 27 versions of the page are identical. [2]

Gmail describes Primary as "Emails from people you know and messages that don't appear in other tabs." With notifications turned on, Gmail alerts you only for Primary. Dragging an email to the right tab teaches Gmail over time; a filter can send one sender to a chosen category every time. [3]

On iPhone, Screen Unknown Callers can be set to Never, Ask Reason for Calling or Silence for numbers not saved in your contacts, and Call Filtering can move missed calls and voicemails from unknown numbers into their own Unknown Callers list. Apple's own advice is to add important numbers to Contacts. [10]

Before you leave the room

1. Save the person with the handles they will actually use. Add the mobile number and the email address they said they'd write from. Adding someone to Contacts is what makes them known in Messages, and a saved number rings through call screening. [4] [10] Our guide to remembering names after a meeting covers what else to write down.
2. Add any second number or address to the same card. A work phone, an assistant's address or a personal email may be treated as a different sender. This is a precaution: Apple doesn't document how it matches a second handle to a contact card.
3. Check the filtered places for a day or two. That means Unknown Senders and Spam in Messages, the other Mail categories and the other Gmail tabs. The time span is our suggestion, not an Apple figure.
4. Rescue and teach in one step. Mark as Known or Create New Contact in Messages, Categorize Sender in Mail, drag to Primary in Gmail. A reply alone doesn't teach the iPhone filter. [1] [2] [3]
5. If you keep screening on, review the notification categories. Of the four, Personal is the obvious candidate for a new acquaintance, where your region lets you choose. [1]

A fictional case

Mina meets Jonah at a conference on a Tuesday and saves "Jonah Reyes, +1 555-0142, jonah@example.com". Her iPhone runs iOS 26 with Screen Unknown Senders turned on.

At 09:10 on Wednesday Jonah texts from his work phone, +1 555-0177, which isn't on the card. The message goes to Unknown Senders, and Mina's phone only alerts her if it falls in a category she allows. On Thursday she finds it, taps Mark as Known, then adds 555-0177 to Jonah's card.

At 14:30 Jonah emails a slide deck from jonah@example.com. In this illustration Mail files it under Updates; Apple doesn't document why a message goes to one category or another, so there is no rule to infer from it. Mina Control-clicks it and categorizes the sender as Primary, and Jonah's later emails land there.

One card with both numbers and the address, filled in before leaving the booth, would have avoided both detours.

Where Kluro fits

Kluro reads the Messages history stored on your Mac. macOS requires Full Disk Access for that protected data, and you choose whether to grant it; the Messages source page explains the connection. Kluro doesn't screen, filter or notify, so the settings above decide what reaches you. Saving a new person with the number and address they really use also gives Kluro's Contacts source the details it uses to recognize people across your connected history.