How can I prevent Microsoft Defender from triggering unwanted one-click unsubscribes?

Summary

Preventing unwanted one-click unsubscribes triggered by Microsoft Defender involves a multi-faceted approach combining technical configurations, email marketing best practices, and proactive monitoring. Experts and documentation sources consistently advise against using direct one-click unsubscribe links in the email body due to the risk of automated scanners activating them. Instead, directing users to a confirmation page requiring an explicit action (like clicking a button) is recommended. Further mitigation strategies include implementing confirmed or double opt-in processes, segmenting engaged subscribers, excluding Microsoft IPs from link tracking, and throttling sending speeds. Proper email authentication (SPF, DKIM, DMARC), configuration of Safe Links settings, and the use of 'mailto:' List-Unsubscribe headers also play crucial roles. Actively monitoring unsubscribe rates, A/B testing unsubscribe link placement and design, establishing feedback loops, and maintaining suppression lists for known bots contribute to a comprehensive defense against unwanted unsubscribes.

Key findings

  • Avoid Direct One-Click Unsubscribes: Direct one-click unsubscribe links in the email body are highly susceptible to being triggered by automated scanners like Microsoft Defender, resulting in unintended unsubscriptions.
  • Confirmation Page is Critical: Directing users to a confirmation page requiring a deliberate action (e.g., clicking a button) to unsubscribe significantly reduces the risk of automated triggers.
  • Proper Authentication is Essential: Correctly implementing SPF, DKIM, and DMARC helps ensure that emails are recognized as legitimate, minimizing the likelihood of being flagged by Microsoft Defender.
  • Engaged Subscribers are Key: Segmenting email lists to target engaged subscribers reduces the chance of sending to inactive addresses that might be scanned and trigger false unsubscriptions.
  • Monitoring is a Must: Closely monitoring unsubscribe rates is crucial for identifying anomalies and promptly investigating potential causes, including Microsoft Defender's activity.

Key considerations

  • Testing is Important: Be cautious when adding new domains and thoroughly test if Office 365 is a vital segment of your user base, as Microsoft Defender's behavior can vary across environments.
  • RFC 8058 Compliance is Important: Adhere to RFC 8058 guidelines for implementing List-Unsubscribe headers to ensure proper handling by email clients and prevent unintended side effects.
  • Maintanence of Suppression Lists is Required: Regularly update and maintain suppression lists of known bot IPs and user agents to prevent them from triggering unsubscribes.
  • Feedback Loops Are Important: Establish and actively utilize feedback loops with Microsoft to gain insights into spam complaints and proactively address potential deliverability issues.
  • Configure Safe Links Settings: Carefully configure Safe Links settings in Microsoft Defender to balance security with the prevention of unintended interactions with unsubscribe links.
  • A/B Testing for Optimisation: Continuously A/B test unsubscribe link placements, design and messaging to improve experience and reduce automatic bot clicks.

What email marketers say
11Marketer opinions

To prevent Microsoft Defender from triggering unwanted one-click unsubscribes, email marketers employ several strategies. These include avoiding one-click unsubscribe links in the email body, implementing confirmed or double opt-in processes, segmenting engaged subscribers, excluding Microsoft IPs from link tracking, monitoring unsubscribe rates for anomalies, and A/B testing unsubscribe link placement. Technical measures include throttling sending speed, maintaining suppression lists of known bots, and utilizing feedback loops to identify issues. Adding a confirmation page after clicking the unsubscribe link adds a layer of protection. Properly implementing RFC8058 guidelines for List-Unsubscribe headers is also recommended.

Key opinions

  • Avoid One-Click Unsubscribes: Placing one-click unsubscribe links in the email body is discouraged as it's often scanned by automated systems like Microsoft Defender, leading to unintentional unsubscribes.
  • Confirmed Opt-in: Using confirmed or double opt-in processes ensures that only genuine subscribers are added to your list, reducing bot-triggered unsubscribes.
  • Segmentation: Segmenting your email list to target engaged subscribers minimizes the risk of sending emails to inactive addresses scanned by Microsoft Defender.
  • Monitor Unsubscribe Rates: Closely monitoring unsubscribe rates helps identify unusual spikes, allowing for proactive investigation and resolution of potential issues like Microsoft Defender's interference.
  • Exclusion of Microsoft IPs: Filtering out Microsoft's IP ranges from link tracking can prevent false positives caused by their automated click-throughs.

Key considerations

  • Test & Verify: Be cautious when adding new domains and thoroughly test if Office 365 is a critical part of your user base, as Microsoft Defender's behavior can vary.
  • RFC 8058 Compliance: Adhere to RFC8058 guidelines for implementing List-Unsubscribe headers to ensure proper handling by MPBs and prevent misuse.
  • Confirmation Pages: Adding a confirmation page after an unsubscribe link click requires users to confirm their decision, reducing accidental or bot-triggered unsubscribes.
  • Suppression Lists: Maintaining a suppression list of known bot IPs and user agents can prevent them from triggering unsubscribes, provided you can identify Microsoft Defender's traffic.
  • Sending Speed: Throttling sending speed avoids triggering spam filters and reduces the likelihood of emails being flagged as suspicious by Microsoft Defender.
  • A/B Testing Placement: A/B test unsubscribe link placement, design, and text, to find which has the best experience with the least amount of automatic clicks.
Marketer view

Email marketer from Reddit explains that closely monitoring your unsubscribe rates and comparing them to industry benchmarks can help identify unusual spikes. If you notice a significant increase, investigate potential causes such as Microsoft Defender's link scanning. This allows you to take proactive measures to address the issue.

September 2022 - Reddit
Marketer view

Email marketer from ActiveCampaign Community suggests excluding Microsoft IPs from link tracking, as their click-throughs can trigger false positives. This involves identifying and filtering out Microsoft's IP ranges in your tracking settings.

November 2023 - ActiveCampaign Community
Marketer view

Email marketer from Email Geeks shares experience with elevated unsubscribe click events due to Microsoft Defender, particularly affecting Office 365 accounts. Recommends escalating the issue to Office 365 for remediation and being cautious when adding new domains, advising testing and verification if Office 365 is crucial to their user base.

January 2025 - Email Geeks
Marketer view

Email marketer from SendGrid shares maintaining a suppression list of known bot IPs and user agents. If you can identify traffic from Microsoft Defender's link scanning, add those IPs and user agents to your suppression list to prevent them from triggering unsubscribes. Suppressing their known signatures can reduce the false unsubscribes.

July 2024 - SendGrid
Marketer view

Email marketer from Neil Patel Blog shares that segmenting your email list to target only engaged subscribers can prevent this issue. Focus on subscribers who have actively opened and clicked on your emails. This reduces the chances of sending emails to inactive addresses that may be scanned by Microsoft Defender, leading to accidental unsubscribes.

August 2024 - Neil Patel Blog
Marketer view

Email marketer from MailPoet explains using a confirmed opt-in process can help. When a new subscriber signs up, they receive an email asking them to confirm their subscription. This ensures that only genuine subscribers are added to your list, which can reduce the likelihood of Microsoft Defender triggering unsubscribes due to bot activity.

September 2022 - MailPoet
Marketer view

Email marketer from Email Geeks echoes Steve's advice and advises against placing one-click unsubscribe links in the email body, as it's often link-checked by MPBs, artificially increasing unsubscribe rates. He also recommends following RFC8058 to implement the feature in email headers appropriately, using one link to a webpage and a POST action for MPBs.

March 2021 - Email Geeks
Marketer view

Email marketer from Stack Overflow explains adding a confirmation page after a user clicks the unsubscribe link can help prevent unwanted unsubscribes. This page requires the user to confirm their decision before the unsubscription is processed, reducing the likelihood of accidental clicks or bot-triggered unsubscribes.

August 2023 - Stack Overflow
Marketer view

Email marketer from EmailToolTester suggests using a double opt-in process for subscribers. Requires users to confirm their subscription by clicking a link in a confirmation email. This ensures valid subscribers, reducing the likelihood of false unsubscribes triggered by bots like Microsoft Defender.

July 2024 - EmailToolTester
Marketer view

Email marketer from Litmus recommends A/B testing different placements and designs for your unsubscribe links. Test how Microsoft Defender interacts with these variations and identify which options are less likely to trigger unwanted unsubscribes. Track which version has the best user experience with the least amount of automatic clicks.

February 2025 - Litmus
Marketer view

Email marketer from Gmass recommends throttling your sending speed to avoid triggering spam filters. Sending emails too quickly can cause Microsoft Defender to flag your emails as suspicious and potentially trigger automated link checks. Gradually increase your sending volume to establish a positive reputation.

July 2023 - Gmass

What the experts say
5Expert opinions

Experts advise against using one-click unsubscribe links due to the risk of automated systems like Microsoft Defender triggering them. Best practice involves directing users to a confirmation page requiring a button click (HTTP POST) to unsubscribe. Link checkers should not unsubscribe users directly from the email body, indicating an incorrect setup if this occurs. Providing an easily accessible unsubscribe option reduces spam reports.

Key opinions

  • Avoid One-Click Unsubscribes: One-click unsubscribe links are susceptible to automated systems triggering them, causing unintended unsubscribes.
  • Confirmation Page: Directing users to a confirmation page with a button click for unsubscription prevents automated systems from unsubscribing users.
  • Incorrect Setup: If a link in the email body immediately unsubscribes a user, it indicates an incorrect setup, as link checkers should not cause unsubscriptions.

Key considerations

  • Accessibility: Provide an easily accessible unsubscribe option to encourage users to opt-out gracefully instead of marking emails as spam.
  • HTTP POST: The unsubscribe mechanism should use an HTTP POST request, triggered by a button click on a confirmation page, to ensure user intent.
Expert view

Expert from Email Geeks explains link checkers should not unsubscribe users, and a click on a link in the email body unsubscribing a recipient indicates an incorrect setup.

April 2023 - Email Geeks
Expert view

Expert from Word to the Wise shares you can protect against crawler unsubscribes by not immediately unsubscribing users who click the unsubscribe link. Instead, direct them to a landing page where they must confirm their decision to unsubscribe. This prevents bots and crawlers from automatically unsubscribing users.

October 2023 - Word to the Wise
Expert view

Expert from Email Geeks explains that clicking a link in the email body should open a webpage for unsubscription confirmation, requiring a button click (HTTP POST) to unsubscribe. He states this has been best practice for a long time, suggesting that immediate unsubscription via a single click should be avoided.

December 2024 - Email Geeks
Expert view

Expert from Spam Resource warns against using one-click unsubscribe links due to the risk of automated systems, including security scanners like Microsoft Defender, triggering them and causing unintended unsubscribes. She emphasizes that these systems don't read instructions and follow links indiscriminately.

August 2021 - Spam Resource
Expert view

Expert from Word to the Wise explains providing an easily accessible unsubscribe option will reduce the likelihood of users marking your messages as spam. Making the unsubscribe process straightforward encourages recipients to opt-out gracefully instead of reporting the email as unwanted.

June 2023 - Word to the Wise

What the documentation says
4Technical articles

To prevent unwanted unsubscribes triggered by Microsoft Defender, documentation recommends configuring Safe Links settings to control link scanning, implementing email authentication protocols (SPF, DKIM, DMARC) to ensure legitimacy, using 'mailto:' List-Unsubscribe headers for confirmation, and setting up Feedback Loops (FBLs) to monitor spam complaints.

Key findings

  • Safe Links Configuration: Adjusting Safe Links settings in Microsoft Defender can reduce automated clicks on unsubscribe links by excluding specific URLs or domains from scanning.
  • Email Authentication: Properly implementing SPF, DKIM, and DMARC ensures emails are recognized as legitimate, reducing the risk of being flagged by Microsoft Defender.
  • Mailto: List-Unsubscribe: Using a 'mailto:' List-Unsubscribe header requires users to confirm unsubscription via email, mitigating accidental unsubscribes from automated checks.
  • Feedback Loops: Setting up FBLs with Microsoft provides data on spam complaints, helping identify and address issues causing emails to be flagged.

Key considerations

  • Authentication Protocols: Ensure correct implementation of SPF, DKIM, and DMARC to validate the origin of emails and prevent false flagging.
  • FBL Setup: Regularly monitor and analyze data from FBLs to understand and address potential issues causing unsubscribes and spam complaints.
  • Safe Links Exceptions: Carefully consider which URLs or domains to exclude from Safe Links scanning to avoid unintended consequences.
Technical article

Documentation from RFC Editor explains that using a 'mailto:' List-Unsubscribe header, rather than a one-click HTTP unsubscribe, may help. The 'mailto:' option requires a user to confirm their unsubscription by sending an email, reducing the risk of accidental unsubscribes triggered by automated link checks.

February 2024 - RFC Editor
Technical article

Documentation from Microsoft explains configuring Safe Links settings in Microsoft Defender for Office 365. By adjusting the settings, you can control how links are scanned and potentially reduce the frequency of automated clicks on unsubscribe links. Consider excluding specific URLs or domains from Safe Links scanning to prevent unwanted interactions.

May 2021 - Microsoft Learn
Technical article

Documentation from Microsoft shares how to implement email authentication protocols (SPF, DKIM, and DMARC) correctly. Proper authentication ensures that your emails are recognized as legitimate, reducing the likelihood of them being flagged by Microsoft Defender and preventing false unsubscribe triggers. It validates that the email truly came from the domain it claims to be from.

March 2022 - Microsoft Learn
Technical article

Documentation from SparkPost explains setting up Feedback Loops (FBLs) with Microsoft. FBLs provide you with data on spam complaints from Microsoft users, allowing you to identify and address potential issues that may be causing your emails to be flagged. It helps you understand and mitigate the reasons behind unsubscribes and spam complaints.

March 2023 - SparkPost

No related resources found.