Setting Outlook spam filter to stop junk email

This article explains why a message can get into a spam folder, how to configure Junk Mail Filter settings in Outlook 365 - 2010 to effectively block spam, and how to remove someone from junk mail.

Email is a crucial communication tool in our daily lives, but unfortunately, it is also a prime target for spammers. Spam emails can be annoying, time-consuming, and harmful. As long as junk emails remain even slightly effective (0.0001%), spam will continue to flood inboxes in massive quantities. Regrettably, the email protocol was created without considering the possibility of sending unsolicited emails, leading to the absence of a 100% protection mechanism. Although it's impossible to eliminate spam completely, you can surely reduce its impact by automatically filtering most unwanted emails to the Outlook spam folder. This will turn a torrent of junk into a manageable trickle.

Fortunately, Outlook provides various tools and techniques to help you fight spam. If you're working in a corporate environment, it's likely that your Exchange server has an anti-spam filter to block unwanted emails. However, for your personal computer, it's up to you to set up your own filter. This article aims to guide you in configuring your Outlook spam filter effectively to block as much junk email as possible.

Note. This article targets classic Outlook for Windows, not the new Outlook.

How Outlook spam filter works

Before delving into setting up the Outlook Junk Mail filter, it's important to have a basic understanding of how it works. Here are some key points to keep in mind:

  • Outlook comes with a built-in spam filter that automatically identifies and moves suspicious emails to the Junk folder, but it doesn't entirely block junk emails from reaching your Outlook.
  • The filter supports various email account types, including Exchange Server accounts, POP3, IMAP, HTTP, Outlook Connector for Outlook.com and IBM Lotus Domino.
  • By default, the Outlook spam filter is set to No Automatic Filtering. However, you can adjust the level of protection for more aggressive filtering.
  • Typically, the Junk Mail filter runs before Outlook email rules come into play. If you're using an Exchange server, remember that its server-side spam filter always has priority. Consequently, any rules you set up won't apply to messages that have been moved to the spam folder already.
  • In newer versions (Outlook 2010 - 365), the spam filter settings are applied to each email account individually. If you have multiple accounts, the Junk Email options dialog will display settings for the account whose folders you're currently viewing.
  • Finally, it's important to note that while the Outlook Junk Email Filter provides significant protection against spam, no filter is foolproof in identifying every unsolicited email, even when set to the highest level. The filter does not pick out any particular sender or a message type. It analyzes each incoming message, taking into account factors like message structure, content, and timing to determine the likelihood of spam.

Outlook spam folder

The Spam folder in Outlook, also known as the Junk folder, is a repository where suspected spam emails are automatically diverted by Outlook's filtering mechanisms. These mechanisms analyze incoming emails based on various criteria such as sender reputation, content, and user behavior to determine whether they are likely to be spam.

Where is the spam folder in Outlook?

The spam folder is typically located in the folder pane on the left side of the Outlook window. Its name may vary slightly depending on the version of Outlook you are using. In the current versions of Outlook 365, the new Outlook, and web app, it is named Junk Email.  If you can't see it, you might need to scroll down or expand the folder list.

Outlook spam folder

How to manage spam folder in Outlook

Make it a habit to check your spam folder regularly. If you find any genuine emails, move them to your inbox and mark them as "not junk" to help train Outlook's filtering algorithms.

  • Viewing spam email. Click on the Junk Email folder to view its contents. Here, you'll find any emails that Outlook has flagged as spam.
  • Restoring legitimate messages. To remove a legitimate message from the spam folder, right-click the message, and then click Junk > Not Junk. The email will be moved to the Inbox folder.
  • Clearing spam folder. To clear the spam folder, right-click it and select Empty Folder from the context menu. This action will move all the messages to the Deleted folder.

By following these simple steps, you can effectively manage the spam folder in Outlook, ensuring that important emails are not overlooked and keep your inbox organized.

How to configure Outlook junk mail settings to automatically filter spam

The Outlook Junk Email Filter automatically scans your incoming emails, but you can adjust its settings to provide the filter with guidance on what to identify as spam. In the below instructions, we'll use Outlook 365, but the settings are essentially the same in all versions of Outlook 2010 - 2021, so you won't have any problems with following.

Note. As each email account has its own Junk Mail settings, be sure to switch to the target account before configuring the junk mail settings.

To enable the Outlook spam filter, carry out these steps:

  1. Access Outlook junk mail settings
  2. Choose spam protection level
  3. Prevent good e-mails from being classified as junk
  4. Block malicious senders
  5. Block top-level domains and encodings

By clicking on the links above, you'll be taken to the section that has all the juicy details about each step.

Junk email settings in Outlook

To get to the Outlook junk email settings, on the Home tab, in the Delete group, click Junk > Junk E-mail Options… Outlook Junk E-mail Options

This opens the Junk E-mail Options dialog box, which is divided into 5 tabs that control various aspects of spam protection. Let's take a brief look at each tab and focus on the essential settings.

Set junk email protection level

On the Options tab, you choose the desired level of spam protection:

  • No Automatic Filtering - no automatic junk mail filtering, but emails from the Blocked Senders list are still moved to the Junk folder.
  • Low - the most tolerant option that filters only the most obvious spam.
  • High - catches most spam emails but may also misidentify legitimate messages and move them to the spam folder. If you choose this option, don't forget to periodically review your Junk mail folder.
  • Safe lists only - the maximum level of protection that only allows emails from people in the Safe Senders and Safe Recipients lists.

Besides the protection levels, two more options are available to you:

  • Permanently delete suspected spam email instead of moving it to Junk folder
  • Warn about suspicious domain names in e-mail addresses (available for any protection level other than No Automatic Filtering)
Choose the level of junk email protection in Outlook.

Tips and notes:

  • It is recommended to test which option works best for you over a short period. If too much spam is still getting into your inbox, switch to the High setting. On the other hand, if too many legitimate emails such as subscribed newsletters are being mistakenly filtered as spam, switch to the Low setting.
  • The Safe Lists Only option may not be the best choice as it requires manually adding safe senders to a list. Any sender not on the list will be filtered as spam, which can include legitimate emails from new clients or customers requesting quotes.
  • Enabling the Permanently delete suspected junk email option leaves no chance to recover a message mistakenly treated as junk. It's advisable to periodically check the spam folder instead of relying on this option.

Prevent good emails to be treated as junk

Using the Safe Senders and Safe Recipients tabs, you can add specific email addresses or domain names to the Safe lists. E-mail messages from anyone on these lists will never be considered spam regardless of their content.

Safe Senders List - allows you to mark email addresses and domain names as safe, preventing them from being treated as junk irrespective of the message content. However, safe domains are not automatically recognized in Exchange Online.

Safe Recipients List - allows you to mark mailing and distribution list senders as safe.

To add someone to your safe list, click the Add button in the right-hand part of the window, and then type an e-mail address or domain name in the pop-up dialog box. Add an email address or domain name to the Safe Senders list.

Tips and notes:

  • To trust all emails from your Contacts or automatically add people you email to the Safe Senders list, select the corresponding option on the Safe Senders tab.
  • If you have an Exchange Server account, all names and email addresses in the Global Address List (GAL) are automatically considered safe.
  • Another way to add a specific contact to the Safe list is to right click a message, click Junk and choose one of the options: Never Block Sender, Never Block Sender's Domain, or Never Block this Group or Mailing List.
  • You can import Safe Senders from a .txt file by clicking the Import from File… button in the right-hand part of the dialog window.

Block malicious senders

On the Blocked Senders tab, you can see email addresses that are already blocked, add more senders to the list or unblock a particular sender. All messages from blocked senders are considered spam and automatically moved to the Junk folder.

To block a sender, click the Add button, and then type an e-mail address or domain name in the pop-up dialog box.

To remove someone from junk, select it in the Blocked Senders list and click the Remove button. Block senders of spam email.

Tip. Another quick way to block a specific spammer is to right-click the message and choose Junk > Block Sender from the context menu. To remove a good contact from junk, choose Never Block Sender.

Quick way to block a specific sender

For more information, please see How to block a sender in Outlook.

Block unwanted email from certain countries or in foreign languages

Spammers often use domains from obscure regions where domain registration is cheap. On the International tab, you can mark certain country domains as spam to stop receiving unsolicited email in foreign languages that you don't know.

This tab provides the following two options:

Blocked Top-Level Domains List. Use this option to block emails from specific countries or regions. For example, if you select IN (India) in the list, you will stop receiving any messages from the .in domain. However, this option may not be effective against junk emails sent from popular email services like Gmail or Outlook.com.

Blocked Encodings List. Use this option to eliminate unwanted e-mail in a specific language encoding. Block top-level domains from specific countries or regions.

Note. Messages that have unknown or unspecified encodings will be filtered by the Junk E-mail Filter in the usual way.

Junk mail settings in Outlook 365 online

If you are using Outlook 365 as a web application (Outlook Online), then you can change junk mail settings by following these steps:

  1. Sign in to Outlook on the web.
  2. At the top of the screen, click Settings (the gear icon), then View all Outlook settings.
  3. In the window that opens, select Mail > Junk email.
  4. Add addresses to the Safe Senders and Domains or Blocked Senders and Domains lists. Change Filters and Reporting as desired.
Junk mail settings in Outlook on the web

Why Blocked Senders list is not the best way to stop junk email

While it may seem that adding unwanted senders to the Blocked list is the easiest solution to prevent spam, this method is not very effective for several reasons:

  • Spammers rarely use the same email address more than once, so adding individual addresses to the Blocked list is a futile effort.
  • For Microsoft Exchange Server accounts, there is a limit of 1024 addresses for the Blocked Senders list and two Safe lists combined.
  • When receiving email, the first thing that Outlook does is check it against the junk filter lists. So, the longer your lists, the slower Outlook will process incoming messages.

Considering the above, the most effective approach is to keep your spam filter lists as short as possible.

However, if you are inundated with an overwhelming number of unwanted emails, you may wonder what you should do. In case numerous spam messages are sent from a particular domain, it makes sense to add it to your Blocked Senders list. To block the entire domain, there is no need to enter sub-domains or use wild characters. You can ban the whole domain by simply entering @spam-domain.com, and this will stop all junk mail coming from that domain.

Tip. Spammers are sneaky and usually send those annoying unsolicited emails from fake addresses that look nothing like the one in the From field. But don't worry, you can try to uncover the real sender's address by taking a peek at the internet headers of a message.

How to keep Outlook Junk Email Filter up to date

Although most spam is easily identifiable, some spammers carefully study Microsoft's spam filter technology to improve their strategies. On the other hand, Microsoft works hard to combat spam and regularly updates their filter to reduce junk email. Therefore, it is advisable to update Outlook regularly to ensure the latest version of the filter is installed.

To enable automatic updates in Outlook, follow these steps:

  1. Start Outlook.
  2. On the File tab, select Office Account.
  3. On the right side, click Update Options > Enable Updates.
Enable automatic updates in Outlook.

Tip. Additionally, you can receive updates for all Microsoft products when you update Windows. For this, click Start > Settings > Update & Security > Windows Security > Windows Update > Advanced Options, and then toggle on the Receive updates for all Microsoft products when you update Windows option.

How to report spam to Microsoft

Even if you have the latest version of the Outlook spam filter, some spam emails may still end up in your inbox. You can assist Microsoft in enhancing the efficiency of their junk email filtering technologies by reporting such messages to them.

Currently, the inbuilt Report button is only available in Outlook on the web (OWA). To report spam to Microsoft, here's what you do:

  1. In Outlook on the web, select one or more unsolicited emails.
  2. On the top menu, click Report, and then select either Report phishing or Report junk.
Report spam to Microsoft.

In desktop Outlook, there is no built-in Report button. As an alternative, you can use free Microsoft Report Message and Report Phishing add-ins. Or you can submit a report through the Microsoft 365 Defender portal.

How to mark an email as not junk in Outlook

Legitimate emails can sometimes be mistaken as spam and moved to the Junk folder. It is important to remember to check this folder occasionally, as no filter is perfect. If you set your Outlook spam filter to the High level to prevent as much junk mail as possible, it is recommended to check your spam folder frequently. Checking it at the end of your workday is a good practice to ensure that you have covered everything.

If a legitimate message appears among junk emails, you can mark it as not junk in this way:

  1. Right click the message, and then click Not Junk.
  2. From the context menu, choose one of the options: Never Block Sender, Never Block Sender's Domain or Not Junk.
Mark an Outlook email as not junk.

Clicking Never Block Sender or Never Block Sender's Domain will add the sender's address or domain name to your Safe Senders list, so the Outlook spam filter won't make the same mistake again.

Choosing Not Junk will move the message from the Junk folder to your Inbox. Additionally, you can select the Always trust e-mail from… option to add that email address to the Safe Senders list. Always trust e-mail from a certain e-mail address.

If you do not wish to add a specific sender to your safe list, you can simply drag a misidentified junk message to any other folder using the mouse.

Note. Emails classified as spam and moved to the Junk folder are automatically converted to plain text format with any links disabled. When you move a message out of the spam folder, its links will be re-enabled and the original message format restored, unless the Junk E-mail filter identifies the links as suspicious. In such cases, even if you move the message out of the Junk folder, the links will remain disabled by default.

How to turn off Junk Mail Filter in Outlook

To turn off Outlook's junk mail filter, this is what you need to do:

  1. In your Outlook, open the Junk E-mail Options dialog box (Home tab > Junk> Junk E-mail Options).
  2. On the Options tab, select No Automatic Filtering. This will stop automatic mail filtering, but messages from the Blocked Senders list will still be moved to the spam folder.
  3. Review the Blocked Senders list and clear it if needed. To have it done, switch to the Blocked Senders tab, select the addresses/domains and click the Remove button. Clear the Blocked Senders list.

In conclusion, spam emails can be frustrating and time-consuming to deal with, but by implementing these tips and tricks, you can successfully prevent them from infiltrating your Outlook inbox. Remember to regularly update your spam filter, block malicious domains, and always be cautious of suspicious emails. With a bit of effort and know-how, you can take control of your email and make sure that only the messages you want are making it to your inbox. Happy emailing!

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113 comments

  1. I have been receiving more and more junk mail from young ladies wanting to date me. I noticed that their addresses always start with a long list of numbers. Is there a way to set a filter to stop all emails coming from sources with the first 5 characters being numbers? Blocking them individually hasn't stemmed the tide.

  2. Hi I have Outlook 2013 on my desktop, and get a lot of Junk mail that I using click Junk, then Block sender, it will put them all in the box, but then the next time I use it, they are all gone and and I have to put them in the junk folder again. Where does the Junk mail go and how do I get them to remain and not have to redo it every time? Thanks Mike

  3. I have upgraded from Outlook 2010 to 2013 (and now running Windows 10) and for some reason I can't figure out how I can set my JUNK MAIL setting (to Low) for each individual email accounts that I have in Outlook

    I have separate 4 separate email POP/SMTP accounts, and all four of them are connected to one OUTLOOK.PST file.

    So, how can I go and setup each ones JUNK MAIL filter. I seem to be only be able to select for the PRIMARY / DEFAULT one.

    Please advise me on what I may be missing.

  4. How can we stop international rubbish Mail coming on RSS on Microsoft outlook. This is annoying and jams up your computer..

  5. How can I keep spam mail from going to my iPhone 6 out of Outlook 2010?
    Everything I have read is the iPhone can't block it only Outlook can. But how?

  6. outllok 2010 does not move junk mail out of my inbox until I click on it. It used to never make it to my inbox. how do I fix it?

  7. I would like to be able to filter & permanently delete email based on one word or phrase in the From field. However, Outlook doesn't seem to allow this. It's necessary because while I get dozens of spams containing "aig" in the From field, few are phrased exactly the same, much the way no 2 email addresses from spammers are exactly alike. And "aig" appears nowhere else in the email. I have maxed out the filters on my Verizon account, so that's no longer an option.

    • As I posted above, I have solved this by using the RULES function. You have so many more options. The one I use is "specific words appear in the senders address" and just entered a text string that always appears. Then simply move the e-mail to the junk folder. I have a couple of rules with things like "smdlv.net" or whatever is being used for the mailing list and it is picking up most of the trash. Good luck with "aig"

    • You CAN send mail to the junk folder or anywhere else using the RULES function. You have a lot more options. I have chosen "specific words appear in the senders address" and just entered a text string that always appears. You can even EXclude other specific words if you have a sender that uses the same mailing list that you want to receive mail from. I have chosen words like "smdlv.net" or whatever always appears at the end. It works. Good luck with "aig"

  8. Hi- the junk email setting works fine for me BUT if I delete all the junk emails then the same spam starts coming back into my inbox and once again I have to start adding them to junk email.

  9. Shame on Microsoft, I regret upgrading to Windows 10, it has no junk mail blocking choice, money, of course, you are diminishing your good name.

  10. Shame on Microsoft, we need to block what we feel as junk; why do you go backwards? Money of course, you are diminishing your good name.Good luck!

  11. I didn't notice if this was addressed or not but we just switched from pop3 to imap for incoming mail. Prior to this switch i rarely received junk in my inbox. Now I'm bombarded and overwhelmed with junk email. I have two offices and I'm using Outlook 2010 on one computer and I believe office 360 on the other. Does that pose any kind of conflict at all. We're thinking maybe we need to switch hosting companies. Any help appreciated, thanks

  12. I really appreciated this page, as somehow my sisters e-mail was accidentally added to the junk bin, I found this page extremely helpful as I searched and searched google for a solution, which I finally found - only on this page, that showed me clearly how to remove her name from the junk list - Thanks AbleBits your help was gratefully appreciated

  13. this relates to outlook 2013

  14. If charlie spammer is sending me emails from ALL of the following (multiple) domains - AND more, do i need to put all those entries in the blocked senders list or is there some shortcut to this madness. I tried putting @domaina.com in the blocked senders list but that does not seem to block any of charlies messages. Any suggestions?

    first.domaina.com
    second.domaina.com
    third.domaina.com
    fourth.domaina.com
    fifth.domaina.com
    sixth.domaina.com
    etc.

    • If you are being plagued by one particular person or company and outlook's junk filter is not working (usually because the domain changes each time) you should be able to set up a "RULE". Go into rules instead of junk and search for a particular string of letters in the senders address and then simply MOVE it to the JUNK folder.

      I am looking forward to trying this as I am getting lots of mail from domains like "@mail16.atl91.mcsv.net" where the numbers keep changing every time.

      I will report back if it works.

      • Yes it does work. You CAN send mail to the junk folder or anywhere else using the RULES function. You have a lot more options. I have chosen "specific words appear in the senders address" and just entered a text string that always appears. You can even EXclude other specific words if you have a sender that uses the same mailing list that you want to receive mail from. Hope this idea helps someone.

        • Thanks you. I will give it a try.

  15. Hi, some of my domain emails do not automatically have a junk folder and others do.
    How can I create a junk folder that junk will automatically go to?
    Thanks
    Sharon

  16. how do I stop emails going into the "Unwanted" file tab when they should be in my inbox?

  17. I have Outlook 2007 by the way...

  18. Hello, is there a way to ensure that .zip files are not accepted in Outlook? We have a virus that is using the names in our contacts list that sends out emails with a .zip file attached which contains the virus... We have run virus scans, removed the viruses, but yet a name will show up from our contacts and the virus file attached. Please help.

  19. how to stop auto send spamming mail in outlook 2003

  20. Svetlana,

    Your article is the most comprehensive one on junk email that I've see so far. Great job!

    I group all the junk emails that I want to block in a folder and I try to click Junk (on the ribbon) and then Block Sender at once. I was able to do this (blocking senders from multiple emails) last week (so I was very happy and recorded the steps) but today, Outlook only allows me to block one email at a time. Very strange. Anyone has any insight? Thanks much!

    • Hello Scarlett,

      Thank you very much for your feedback!

      Outlook allows you only to block a particular sender, it does not support blocking multiple emails you select. There are third-party tools that let you do this, but no standard way except for blocking them one by one.

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