How to Block Emails in Outlook: Senders and Domains
Outlook moves blocked senders to Junk Email. You can block one address or a whole domain.
By Siddharth ShankarUpdated October 22, 2026In the new Outlook for Windows, go to Settings, Mail, Junk email, then add an address under Blocked senders or a domain under Blocked domains. In classic Outlook, right-click a message and choose Block, then Block Sender. Microsoft says blocked mail is moved to Junk Email, which is cleared after 14 days. The blocked list holds up to 10,000 addresses and domains, and the new Outlook cannot block senders for third-party accounts such as Gmail.
Your email is the key to most of your accounts. Has it already leaked?
Free · About 30 seconds · No sign-up · Email not stored
Outlook has two common versions, and the steps differ. This guide follows Microsoft’s own help pages for the new Outlook for Windows and for classic Outlook on Windows.
New Outlook for Windows
Microsoft gives these steps. Pick the account you want to change if you have more than one. Open Settings, choose Mail, then Junk email. To block one address, enter it under Blocked senders and select Add. To block a whole domain, enter the domain name under Blocked domains and select Add. Save your changes.
To unblock, return to the same screen, select the address or domain and click the remove icon.
Classic Outlook on Windows
Right-click a message from the sender, then choose Block and Block Sender. Another route is to select the message, go to Home, Delete, Junk and choose Block Sender.
To manage the list yourself, go to Home, Delete, Block, Junk E-mail Options and open the Blocked Senders tab. Choose Add, then type a full address such as someone@example.com or a domain such as example.com.
Quick check before you read on: is your email in a known data breach? Free, about 30 seconds.
Free · About 30 seconds · No sign-up · Email not stored
What happens to blocked mail
Microsoft says Outlook moves messages from a blocked sender to the Junk Email folder. In classic Outlook the page says mail from a blocked address or domain is treated as junk regardless of its content. Junk mail is removed from the Junk Email folder after 14 days and cannot be recovered after that, so check the folder if you expect a message from someone.
Limits worth knowing
- List size. The blocked senders and safe senders lists can hold up to 10,000 addresses or domains in total. If you need more, block domains instead of single addresses.
- Third-party accounts. The new Outlook does not support blocking senders for accounts such as Gmail, so set the block with that provider.
- Exchange accounts. Names in the Global Address List are treated as safe and cannot be added to the blocked list.
- Diverting, not stopping. The filter does not stop junk from being delivered. It sends it to the Junk Email folder.
Safe senders
If a real sender lands in Junk, select a message from them and choose Block, then Never Block Sender in classic Outlook. If your mailbox is on Exchange, Microsoft warns that changes to Safe Senders may not be recognised, so contact your administrator.
When blocking is not enough
A block is address based. A sender who writes from a new address starts again. Reduce the supply by giving websites an Outlook alias, and check whether your address has appeared in a breach.
Sources
- Microsoft: Block or unblock senders in Outlook (new Outlook steps, Junk email behaviour, 14 days, 10,000 limit, third-party accounts)
- Microsoft: Block a mail sender in Outlook (classic Outlook steps, Blocked Senders list, Safe Senders, Exchange notes)
Frequently asked questions
Where does blocked mail go in Outlook?
Microsoft says Outlook moves it to the Junk Email folder, which is cleared after 14 days.
Can I block a whole domain?
Yes. In the new Outlook, add it under Blocked domains. In classic Outlook, add a domain such as example.com in the Blocked Senders tab.
How many senders can I block?
Microsoft says up to 10,000 addresses or domains across the blocked and safe senders lists.
Can new Outlook block senders in my Gmail account?
No. Microsoft says the new Outlook does not support blocking for third-party accounts such as Gmail.
Does blocking stop the email being delivered?
No. It diverts mail to Junk Email rather than stopping delivery.
See if your email has already leaked
- Checks your email against known data breaches
- Shows which sites leaked it, when, and what leaked
- We do not store the email you check
Compare data removal services
See which services work in your country, what they cost, and the free do-it-yourself route.
Compare removal services →Prefer a one-time report first? Scan My Shadow, our sister service, $9.99.