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How to Fix Outlook Spam Filter Not Working?

  author
Jamie Kaler   Contribution
Rollins Duke
Rollins Duke  Approved By
Published On March 24th, 2026 • 6 min read

Have you opened Outlook and found the inbox flooded with promotional emails, phishing attempts, etc.? You are not alone. This is one of the frustrating problems Outlook users face. If the spam emails are landing in the inbox or emails are disappearing from the junk folders, even after setting up the spam filter. We will therefore get to the solution to fix the Outlook spam filter not working properly from here.

The article will provide everything you need to know about this situation: what the Outlook spam filter is, why it is not working properly, and possible reasons for its failure.

What is Outlook Spam Filter?

Outlook’s spam filter, which is Junk Email Filter, is a built-in feature that is designed to automatically identify and divert unwanted or potentially harmful emails from the email inbox. It works by analysing several characteristics of incoming messages that include:

  • Message content, embedded links, subject lines.
  • Sender reputation and email address patterns.
  • Known spam databases and blacklisted domains

In Outlook desktop, the spam folder filter works with Microsoft’s Exchange Online Protection (EOP) and

What Does “Outlook Spam Filter Not Working” Mean?

When we say the Outlook spam filter is not working, it means one of the two problems:

  • Spam Emails are coming to the Inbox Folder: Any junk, promotional, malicious emails, etc., bypass the junk folder and enter the main inbox, creating clutter in the email account.
  • Important Emails Marked as Spam: When emails from trusted contacts, or important services, end up in the spam folder, which cause missed communication and workflow disruptions. It is also known as a false positive.

These situations say that the spam filter is not working, outdated or overridden by having any conflicting settings.

All Reasons Why the Outlook Spam Filter is Not Working

There are numerous reasons why the Outlook spam filter might fail to function. Here is a comprehensive breakdown of what possible causes are:

  • Junk Email Filter is Disabled: The common reason is that the junk email filter is turned off or set to “No Automatic Filtering.”
  • Outdated Junk Filter Settings: The Outlook spam filter relies on regularly updated filter definitions that understand the spam patterns and malicious senders.
  • Misconfigured Safe or Blocked Senders list: If the spam sender’s email address or domain is accidentally added to the safe senders list, then Outlook will allow the messages to go through regardless of the content.
  • Inbox Rules Redirecting Spam to the Inbox: It could be due to Outlook inbox rules. Some of the rules may inadvertently move the junk emails from the spam folder to the inbox, which could be the reason for “Outlook Spam Filter Not Working”.
  • Outlook Profile Corruption: A corrupted Outlook can cause many features to malfunction, including the spam filter.
  • Damaged Outlook Data File: Outlook files can become oversized or get damaged; this can affect the overall Outlook performance, including the spam filtering.

Step-by-Step Solutions to Fix the Outlook Spam Filter Not Working Issue

Here are some of the troubleshooting steps to work on resolving the Outlook spam filters. The steps below are some of the common troubleshooting methods to bring the spam filter back to work properly.

Check Junk Email Filter Setting

Ensure the spam filter is properly configured or not:

  • Open an Outlook account.
  • Go to the Home menu.
  • Click Junk > Junk Email Options.
  • Select an appropriate protection level.

Pro Tip: Set it to High for stronger filtering.

Verify the Blocked and Safe Senders Lists if “Outlook Spam Filter Not Working”

  1. Go to the Junk Email Options.
  2. Check the safe senders list and remove the unnecessary entries.
  3. Add any suspicious senders to the blocked senders list.

Update Outlook Application

An outdated version can cause filtering issues. Ensure to update the Outlook application:

  1. Go to File > Office Account.
  2. Click Update Options > Update Now.

Review Inbox Rules If Outlook Junk Filter Not Working

If you have Outlook rules set up, it might override the spam filter. Check the inbox rules:

  1. Go to File > Manage Rules & Alerts.
  2. Review all rules carefully.
  3. Disable or delete conflicting rules.
Check Out: Corrupted or conflicting rules are one of the top causes of spam filter failure. After checking and resettings doesn’t fix, check out the article – Outlook rules Not Working Properly.

Check the Focused Inbox Settings

Focused inbox can sometimes misplace the emails:

  1. Go to the View tab.
  2. Turn off Focused Inbox.
  3. Check if Spam Filtering improves.
Disable Suspicious Add-ins and Fix “Outlook Spam filter not working”

Add-ins can interfere with Outlook functionality:

  1. Go to File > Options > Add-ins.
  2. Click on Go under Manage COM Add-ins.
  3. Uncheck the unnecessary add-ins and restart Outlook.

This add-in could also cause other issues with Outlook, in which one of the prominent one is – Outlook app closes immediately after opening.

Run Outlook in Safe Mode

Opening Outlook in safe mode helps to identify the issues with the extension:

  1. Press Windows + R.
  2. Or Type: outlook.exe /safe
  3. Press Enter.

Check if the spam filter is working in safe mode; then the issue is most likely due to add-ins.

Repair Outlook Data Files

Any corruption in the PST/OST file can cause issues with the features in Outlook.

  1. Close Outlook completely before running the repair tool.
  2. Locate the ScanPST.exe tool. It is usually found in: c:\Program Files\Microsoft Office\root\OfficeXX\ (Replace XX with the Office version)
  3. Double-click the ScanPST.exe to open the Inbox Repair Tool.
  4. Click on Browse and select the PST/OST data file.
  5. Click on the Start button to begin the scanning.
  6. Once the scan is complete, click Repair to fix the detected errors.
  7. Restart Outlook and check if the spam filter is working properly
Create New Outlook Profile to Resolve “Outlook Spam Filter Not Working”

If the Outlook profile is corrupted, it can break spam filtering.

  • Go to Control Panel > Mail.
  • Click on Show Profile.
  • Create a new profile and set it as the default.
Check Server-Side Spam Filter

If you are using Outlook with Exchange or Microsoft 365:

  1. Log in to Outlook Web App.
  2. Go to Settings > Mail > Junk Email
  3. Adjust filtering settings.
Precautionary Steps for “Outlook spam filter not working” Issue: Use a Tool to Preserve Emails

If you have to make any changes to the spam filter settings, inbox rules, or Outlook configuration, it is recommended to create a backup of the emails. Use the Outlook.com Backup Tool here as a solution. Why is this important, as the vital emails may already be in the junk folder and could be auto-deleted if not sorted out before. Any changes to the filter rules can sometimes cause accidental deletion of the emails.

The tool allows exporting, saving, and archiving the emails in various formats such as PST, MBOX, MSG, PDF, DOC, etc. It also has the filter option that gives you the option to back up selective emails you need.