- What blocking a sender in Outlook really does
- Blocking a sender from a message in classic Outlook
- Adding an address or domain by hand in classic Outlook
- Blocking emails in Outlook on the web
- Blocking versus other ways to quieten an Outlook sender
- Unblocking a sender in Outlook
- Checking your Outlook Junk folder after blocking
- When blocking emails in Outlook isn't enough
- Frequently asked questions
To block emails in Outlook, right-click a message and choose Block, then Block Sender, or add the address in Junk email settings on the web. Microsoft says blocked mail goes to your Junk Email folder, and the sender can still send it.
There's always one sender who won't take the hint: the supplier who emails twice a week, the list you never joined, or the old contact who keeps copying you in. Outlook can quietly shove them out of your sight, but it works differently from what many people expect.
Blocking in Outlook doesn't stop the email being sent. It sends it to your Junk Email folder instead. That's a useful difference to understand before you rely on it, so I'll start there and then take you through each version.
What blocking a sender in Outlook really does
Microsoft's help page says messages from a blocked sender are immediately moved to the Junk Email folder. It also says the blocked sender can still send you email, because blocking only diverts it.
- Blocked mail goes to Junk Email, so it isn't deleted for good.
- Your organization may send it to End-User Quarantine instead, if your administrator has turned that on.
- People in your organization's Global Address List are treated as safe, and Microsoft says they can't be added to the blocked list.
That last point matters at work. If a colleague is flooding you with messages, blocking won't help, and a quiet word or a rule is the better route.
Blocking a sender from a message in classic Outlook
- Right-click a message from the sender.
- Select Block, then Block Sender.
Another route is to select the message, go to the Home tab, and in the Delete group choose Junk, then Block Sender. Menus vary between versions, so if one doesn't match your screen, try the other.
Adding an address or domain by hand in classic Outlook
If you want to block someone before they email you, or stop everything from one company, type the details in yourself:
- On the Home tab, in the Delete group, select Block, then Junk E-mail Options.
- Open the Blocked Senders tab and select Add.
- Enter an email address, or a domain such as example.com, and select OK.
- Repeat for any others.
To change or remove an entry later, select it and choose Edit or Remove.
Blocking emails in Outlook on the web
According to Microsoft's junk email settings page, go to Settings, then Mail, then Junk email. Under Blocked senders, type the address and select Add. To block a whole domain, enter it under Blocked domains and select Add. Then select Save.
Microsoft says you can have up to 10,000 addresses or domains in the blocked senders and safe senders lists, which is far more than most of us will ever need. It also notes that the server hosting your mailbox may have its own junk filtering that acts before mail reaches you, in which case your administrator would need to change those settings.
| Where | How to start |
|---|---|
| Classic Outlook, from a message | Right-click the message, then Block, then Block Sender |
| Classic Outlook, by hand | Home, Block, Junk E-mail Options, Blocked Senders tab |
| Outlook on the web | Settings, Mail, Junk email, Blocked senders |
Blocking versus other ways to quieten an Outlook sender
Blocking is the blunt tool. Before you reach for it, think about whether something gentler does the job, because a blocked sender goes to Junk and out of your mind, which isn't always what you want.
| Situation | A better first step |
|---|---|
| A newsletter you signed up for | Use the unsubscribe link |
| A supplier or client who emails too often | Ask them to cut down, or file their mail in a folder |
| Someone sending unwanted offers | Block the sender |
| A whole company flooding you | Block the domain, once you've checked nobody useful works there |
Think about the consequences for domains in particular. If you block a domain that a customer also uses, their emails will go into Junk and you may not see them for days. I'd only block a domain I'm sure about, and I'd check Junk regularly afterwards.
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Unblocking a sender in Outlook
Changed your mind? In classic Outlook, open Junk E-mail Options, select the entry on the Blocked Senders tab and choose Remove. On the web, go back to Junk email in Settings and remove the address or domain from the list.
Microsoft also describes a safe sender option. In classic Outlook, select a message, choose Block, then Never Block Sender, and its mail is kept out of Junk. It's the right tool for a client whose emails keep ending up in the wrong place.
Checking your Outlook Junk folder after blocking
Microsoft advises looking through the Junk folder from time to time so you don't miss anything important. That applies doubly to anyone running a business, where one missed enquiry can be a lost job. Add a weekly glance at Junk to your routine, especially after you've blocked a domain, because a blocked domain catches everybody at that company.
A tidy inbox needs more than a block list. My story about the email management system that saved my inbox covers the folders and habits that sit alongside blocking.
When blocking emails in Outlook isn't enough
- Unwanted newsletters: use the unsubscribe link first, because a real sender will stop.
- Messages that look like phishing: don't reply or click links. Report them through your organization or email provider.
- Harassment or threats: keep the messages, report it, and if you're in danger contact the police.
- A colleague or client you can't block: set up a rule to file their emails, or talk to them.
For a rule that sorts mail instead of blocking it, see my guide to managing email overload, which covers the habits that make blocking a last resort.
Frequently asked questions
How do I block an email address in Outlook?
In classic Outlook, right-click a message from the sender and choose Block, then Block Sender. On the web, go to Settings, Mail, Junk email and add the address under Blocked senders.
Where do blocked Outlook emails go?
Microsoft says they're moved to the Junk Email folder, or to End-User Quarantine if your administrator has enabled it.
Can a blocked sender still email me?
Yes. Microsoft says the blocked sender can still send you email, because blocking only diverts it.
Can I block a whole domain in Outlook?
Yes. In classic Outlook you can add a domain on the Blocked Senders tab. On the web, Microsoft's page lists a Blocked domains box in Junk email settings.
How do I unblock someone in Outlook?
Open Junk E-mail Options in classic Outlook, select the entry on the Blocked Senders tab and choose Remove. On the web, remove it from the list in Settings, Mail, Junk email.
