Why are email open rates dropping for Hotmail and Live accounts?
Matthew Whittaker
Co-founder & CTO, Suped
Published 20 Jun 2025
Updated 16 Aug 2025
7 min read
Many email marketers have recently noticed a concerning trend: a significant drop in email open rates for Hotmail and Live accounts. This issue isn't isolated, impacting various accounts and countries. It signals a shift in how Microsoft's mail systems are processing incoming emails, potentially leading to widespread deliverability challenges. Understanding the root causes is the first step toward addressing these declines and restoring your email campaign performance.
While email open rates are no longer a perfectly accurate metric due to privacy features like Apple Mail Privacy Protection, a sudden and steep decline, particularly with specific providers like Microsoft (Hotmail, Outlook, Live), often points to an underlying deliverability problem. Your emails might not even be reaching the inbox, instead landing in spam or being outright blocked. This can severely impact engagement metrics, including click-through rates and conversions.
This situation has prompted many discussions among email professionals, with reports indicating a significant drop in inbox rates starting around March 2023. These shifts underscore the dynamic nature of email deliverability and the need for senders to remain vigilant and adaptable.
Possible causes of the drop
The primary reason for a sudden decrease in open rates for Hotmail and Live accounts is typically due to changes in Microsoft's spam filtering algorithms. These changes can make filters more aggressive, leading to legitimate emails being caught. It is not uncommon for mail providers to adjust their filtering mechanisms to combat evolving spam tactics, and sometimes, this can inadvertently affect legitimate senders.
When filters become stricter, even minor compliance issues or historical sender reputation flags can lead to emails being diverted from the primary inbox. This means that emails that previously delivered successfully might now be landing in the junk folder, or worse, being rejected entirely, leading to a perceived drop in opens. For more details on common causes, you can refer to our guide on what causes a sudden drop in email open rates.
While it might seem like a global issue affecting all senders uniformly, the impact can vary. Senders with stronger, more consistent email practices may experience less severe drops, or none at all. Those who were operating close to the edge of what Microsoft's filters consider acceptable are often the first to see a significant impact when these thresholds are adjusted. This highlights the importance of maintaining robust email hygiene and authentication practices at all times.
Old filtering behavior
Permissive thresholds: Allowed a broader range of sender behaviors before flagging emails as spam.
Focus on blatant spam: Primarily targeted obvious spam patterns and known malicious senders.
Lower sensitivity: Less sensitive to marginal compliance issues, leading to higher inbox placement for some senders.
In the past, Microsoft's filters were more lenient, allowing a wider variety of email practices without immediate negative consequences. This meant that some senders could get away with less stringent list hygiene or less rigorous adherence to email best practices.
Before algorithm changes
Higher perceived open rates: Emails often reached the primary inbox more easily, resulting in higher reported open rates, even for campaigns with minor issues.
Lenient filtering: Less aggressive spam filters meant fewer legitimate emails were caught in the net.
Focus on engagement: Emphasis was more on user engagement signals rather than strict policy enforcement.
After algorithm changes
Lower actual open rates: Emails are more likely to land in spam, leading to a real decrease in opens and engagement.
Aggressive filtering: New algorithms target a wider range of potentially unwanted mail, including those with subtle issues.
Stricter policy enforcement: Increased scrutiny on sender reputation, authentication, and content compliance.
Impact on email deliverability
When open rates for Hotmail and Live accounts decline, it's often a symptom of broader deliverability challenges. Your emails may be consistently routed to the spam folder, or even rejected before they reach the recipient's mailbox. This directly impacts your campaign's effectiveness, as even the best content can't be read if it never reaches the intended audience.
A low open rate can indicate a problem with your sender reputation. Email service providers like Microsoft use complex algorithms that consider various factors, including past engagement, spam complaints, and adherence to email authentication standards (like DMARC, SPF, and DKIM) to determine inbox placement. A sudden drop suggests that one or more of these factors might have triggered a negative response from Microsoft's filters.
Moreover, if your emails are consistently ending up in spam, it can lead to further erosion of your sender reputation over time. Recipients who don't see your emails cannot engage with them, which in turn sends negative signals back to Microsoft's filters, creating a vicious cycle. Addressing these deliverability issues is crucial for maintaining a healthy sending relationship with Hotmail and Live.
How to diagnose and address the issue
The first step in diagnosing a drop in open rates is to leverage available tools and resources. Microsoft provides a service called Sender Network Data Services (SNDS), which offers insights into your sending reputation and potential issues. Registering your IPs and domains with SNDS can provide valuable diagnostic information.
Next, systematically review your email practices. This includes verifying your email authentication records (SPF, DKIM, DMARC), ensuring your sending IPs or domains are not listed on major email blocklists (or blacklists), and analyzing recent campaign metrics beyond just open rates, such as click-through rates and bounce rates. These steps can help pinpoint specific issues contributing to the problem.
If initial diagnostics don't reveal a clear cause or if the problem persists, filing a support ticket with Microsoft's Postmaster team is advisable. Provide as much detail as possible about your sending infrastructure, the nature of your emails, and the observed drop in open rates. Some senders have found success by escalating these tickets to receive a resolution. This is a common course of action, as evidenced by similar experiences shared in online communities, such as this discussion about deliverability issues.
Here's how to check if your domain or IP is on a blocklist (blacklist):
To prevent future drops in open rates and ensure long-term success with Hotmail and Live, focus on building and maintaining a strong sender reputation. This involves a multifaceted approach that goes beyond just troubleshooting immediate problems. It's about proactive management of your email program.
Prioritize list hygiene by regularly cleaning your email lists to remove inactive subscribers, invalid addresses, and known spam traps. Engaging with a healthy, active list signals to ISPs that your emails are valued, which positively influences your sender score. Implementing strong email authentication protocols (SPF, DKIM, and DMARC) is also non-negotiable, as it proves your legitimacy and prevents spoofing.
Continuously monitor your email deliverability and engagement metrics, paying close attention to blocklist status and complaint rates specifically for Microsoft properties. Adapt your content and sending frequency based on subscriber feedback and performance trends. For more guidance on this, our article on how to comply with Outlook's new sender requirements can be a valuable resource.
Best practices for Microsoft deliverability
Implement DMARC, SPF, and DKIM: Essential for authenticating your emails and proving legitimacy.
Maintain list hygiene: Regularly clean your subscriber lists to remove inactive or invalid addresses.
Monitor feedback loops: Pay attention to spam complaints through Microsoft's SNDS feedback loop.
Provide clear unsubscribe options: Make it easy for recipients to opt out, reducing spam complaints.
Segment and personalize: Send relevant content to increase engagement and reduce spam reports.
Maintaining email health
A sudden drop in open rates for Hotmail and Live accounts can be alarming, but it is often a solvable issue. By understanding the common causes, proactively diagnosing problems, and implementing best practices for email deliverability, you can improve your inbox placement and regain recipient trust. Continuous monitoring and a commitment to email hygiene are key to navigating the ever-changing landscape of email filtering and ensuring your messages reach their intended audience.
Remember that email deliverability is an ongoing process, not a one-time fix. Microsoft, like other major email providers, constantly refines its spam filters to protect users from unwanted mail. Staying informed about these changes and adapting your sending strategy accordingly will help maintain strong sender reputation and optimal open rates.
Views from the trenches
Best practices
Actively use Microsoft's SNDS for insights into your sending reputation and to monitor for any issues.
Regularly clean your email lists to ensure you are sending to engaged, valid subscribers, which improves sender signals.
Implement and maintain DMARC, SPF, and DKIM records to ensure your emails are authenticated and trusted by Microsoft.
Segment your audience and personalize content to increase engagement and reduce the likelihood of spam complaints.
Provide an easy and clear unsubscribe option in all emails to minimize complaints and maintain a healthy list.
Common pitfalls
Ignoring a sudden drop in open rates, assuming it's a temporary glitch without deeper investigation.
Failing to monitor Microsoft's Postmaster tools and SNDS for specific feedback on your sending practices.
Neglecting list hygiene, leading to sending emails to unengaged recipients or spam traps, which hurts reputation.
Not having proper email authentication (SPF, DKIM, DMARC) in place, making your emails appear less trustworthy.
Sending inconsistent or irrelevant content that leads to low engagement and higher spam complaint rates.
Expert tips
If experiencing deliverability issues with Hotmail/Live, file a support ticket with Microsoft and push for escalation.
Recognize that Microsoft's filters are dynamic; what worked yesterday might not work today, requiring continuous adaptation.
Focus on engagement metrics beyond opens, such as clicks and conversions, as open rates can be skewed by privacy features.
Understand that sometimes, if your emails are getting caught by new aggressive filters, it might mean your prior practices were 'sloppy'.
A freemium model could sometimes exempt clients from deliverability issues, indicating the impact varies across sender types.
Marketer view
A marketer from Email Geeks says they received an alert on March 13, 2023, stating that several senders had reported a significant drop in inbox rates at Outlook starting on March 10, 2023. This issue was at Outlook and was being investigated.
March 13, 2023 - Email Geeks
Expert view
An expert from Email Geeks says they have seen multiple reports of people having problems and the current advice is to file a ticket and ask for escalation until it gets resolved.
Microsoft (Hotmail, Outlook, Live), often points to an underlying deliverability problem. Your emails might not even be reaching the inbox, instead landing in spam or being outright blocked. This can severely impact engagement metrics, including click-through rates and conversions.
Sender Network Data Services (SNDS), which offers insights into your sending reputation and potential issues. Registering your IPs and domains with SNDS can provide valuable diagnostic information.
