How to block a sender in Outlook on Mac: new and legacy steps for 2026

Blocking a sender in Outlook on Mac is a short job. The steps are simple, but the effect is smaller than most people expect. Blocking sends that sender's mail to Junk. It does not erase the address, and it does not stop the messages from reaching your account. Read the limits below before you rely on it.

Block a sender in Outlook on Mac, step by step

You need Outlook for Mac open and at least one message from the sender in your list. Microsoft's current Mac article uses the Toolbar route, so start there. The steps in this section follow that route. Older menu paths come later in this guide.

The right-click and legacy menu routes

Some people see a Block option when they right-click a message. Microsoft's junk article describes right-click, then Junk Mail, then Block Sender. A University of Waterloo IT guide describes right-click, Block, then OK for new Outlook. That guide is not from Microsoft, so treat it as a second opinion.

• Right-click or Control-click the message header, then choose Junk Mail > Block Sender. Source: Microsoft's junk email article.
• Legacy Outlook: select the message, then go to Home > Junk > Block Sender. Source: Microsoft's block article.
• New Outlook: right-click the email, choose Block, then click OK. Source: University of Waterloo, not Microsoft.
• A 2023 Microsoft Q&A answer gives Message > Junk Mail > Block Sender. The thread is tagged legacy, so use it only when the other routes are missing.

The menu names do not match from page to page. Microsoft's Mac article says Toolbar > Block, its legacy section says Home > Junk > Block Sender, and the 2023 answer says Message > Junk Mail > Block Sender. Match the path to what you see on your screen, not to whichever article you found first.

What blocking does to the mail you receive

This is the part most guides skip. A Microsoft Q&A moderator says Block Sender moves messages to Junk rather than blocking delivery. The same answer says Outlook for Mac has no native server-side blocking. So the sender can still reach your account. You just stop seeing their mail in the inbox.

The figures above describe Microsoft's scale, not your inbox. Blocking one address does nothing to a message that arrives from a different one. You may need to block each address you see, or build a rule instead.

How to unblock a sender in Outlook on Mac

Unblocking reverses the same setting. Microsoft's Mac article puts it under Junk Email Preferences, in the Blocked Senders tab. Select the address or the domain, then click Remove the selected sender. Mail from that sender should then stop going to Junk because of the block.

• Click Outlook in the menu bar, then choose Tools > Junk Email Preferences.
• Open the Blocked Senders tab.
• Select the address or domain, then click Remove the selected sender.
• Legacy Outlook restore: select a message from that sender, then choose Home > Junk > Not Spam.
• New Outlook: go to the Outlook tab, choose Settings > Junk > Blocked Senders, select the address, then click the minus icon. Source: University of Waterloo, not Microsoft.

Block a sender in Outlook on the web

If you read mail in a browser, the steps change. Microsoft's web article uses Settings > Mail > Junk email. Enter the address under Blocked senders, select Add, then select Save. If you have more than one account, select the account first. The same article lists Blocked domains as a separate field.

Check your Outlook version before you block

Legacy Outlook for Mac is the older app. Microsoft's features page says support for it would end in October 2026, depending on the license. A centrexIT article dated September 17, 2026 says legacy Outlook stops working against Exchange Online mailboxes that month. I could not confirm what happened after that date, so test these steps on your own Mac.

The newest Outlook for Mac build I could verify is 16.114.3, build 26102720, released October 27, 2026. Newer builds may exist. Microsoft's release notes for Office for Mac are the place to check for later changes to the block menu.

Which accounts can block senders

The account type decides which route you can use. Microsoft's block article says blocking works on Exchange-based accounts. Its junk article says junk protection covers every supported account except Exchange. The table sets out the practical result.

Mistakes that make blocking look broken

• Blocking one address when the sender writes from another. Check the From line on the next message before you decide the block failed.
• Looking only in the inbox. Blocked mail goes to Junk, so search there first.
• Expecting unsubscribe to finish the job. One Microsoft Q&A user reported unwanted mail still arriving after unsubscribing, and that thread has no accepted fix.
• Blocking a colleague or client by accident. Their mail goes to Junk too, so tell them if the change matters to your work.
• Trusting an old menu name. Microsoft's pages name the Block control differently, so match the path to your screen.

Keyboard shortcuts for junk mail on Mac

Outlook for Mac has shortcuts for marking junk, but none for blocking. Command+Shift+J (⌘⇧J) marks the selected message as junk. Command+Shift+Option+J (⌘⇧⌥J) marks it as not junk. Microsoft's shortcut page covers Outlook for Microsoft 365, 2024, and 2021 for Mac, so confirm the keys on your own Mac first.

Blocking does not stop phishing

A blocked sender is not a security control. Microsoft's Digital Defense Report says 89 to 95% of email phishing attachments led to a credential theft effort, and it gives no time window for that figure. The same report says more than 145 million QR-code phishing attacks were detected by Defender for Office 365 between July 2025 and June 2026.

Blocking helps with mail you never want. It does not tell you whether a message is safe. Treat unexpected requests for passwords or payments as suspect, even from a sender you have not blocked.

When one block is not enough

A common workaround is an inbox rule that matches the sender's address. A Microsoft Q&A moderator suggested a rule with From contains the address, then Delete. Deleted mail cannot be recovered. Move the mail to a folder you check instead, so you keep a record. The create a rule in Outlook on Mac guide covers the rule steps.

Long lists are a poor fit for a single sender. Microsoft's Windows help says blocked and safe lists together can hold up to 10,000 entries, and it suggests blocking domains beyond that. The same page says items in Junk Email are removed after 14 days. That page covers Windows, so I did not confirm either number on Mac.

Where to go next

If you need older mail from a sender before you decide, use search with filters in Outlook on Mac. If the account setup is the real problem, the add an email account in Outlook on Mac guide covers new and legacy setup.