Why are my emails going to the spam folder in Hotmail / Microsoft even with good click to open rates?
Matthew Whittaker
Co-founder & CTO, Suped
Published 8 Aug 2025
Updated 15 Aug 2025
7 min read
It can be incredibly frustrating when your emails land in the spam or junk folder, especially when your analytics show strong engagement metrics like good click-to-open rates. This issue is particularly common with Microsoft domains, including Hotmail and Outlook. You might be wondering, if recipients are actively clicking on my emails, why are they still not consistently reaching the inbox?
The challenge with Microsoft's email filtering lies in its sophisticated, multi-layered approach. It's not a simple binary decision of inbox or spam, but a complex interplay of various factors beyond just initial engagement. Let's explore the underlying reasons and how to address them to improve your deliverability to Microsoft inboxes.
Understanding Microsoft's filtering dynamics
One common misconception is that if an email has a high click-to-open rate, it must be reaching the inbox. However, with sophisticated spam filters, a portion of your emails might still be diverted to the junk folder, and only the emails that successfully land in the inbox contribute to your observed click-to-open rates. This means your deliverability to the inbox is lower than you perceive, even if the engagement on the delivered portion is excellent.
Microsoft's systems (including Hotmail and Outlook) employ advanced algorithms that analyze numerous signals. These signals go beyond simple opens and clicks, looking at how users interact with your emails over time, how often they move your emails from junk to inbox, and whether they mark your emails as safe senders. If many recipients mark your emails as spam, even if others click, it can negatively impact your sender reputation. For more details on how the Junk Email Filter works, Microsoft provides helpful resources.
This situation points to a potential issue with your sender reputation or other underlying deliverability factors. When Microsoft's systems detect inconsistencies, they might flag your domain or IP as suspicious, leading to emails being junked despite positive user actions from a subset of your audience. The challenge is often that Microsoft's feedback loops are not always explicit or easy to interpret.
Sender reputation and authentication
A primary reason for emails consistently going to the spam or junk folder is often related to sender reputation. This encompasses the reputation of your sending IP address and your domain. Even if your emails have high click-through rates, a poor overall reputation can lead to filtering, especially by strict Mailbox Providers (MBPs) like Microsoft. Your reputation is influenced by various factors, including spam complaints, bounce rates, and overall engagement patterns, not just clicks.
Email authentication is another critical component. Properly configured SPF, DKIM, and DMARC records signal to receiving servers that your emails are legitimate and from an authorized sender. Without these, even well-intentioned emails can be flagged as suspicious. Microsoft and Yahoo have recently implemented stricter authentication requirements, making proper setup more crucial than ever. This includes ensuring your DMARC policy is correctly configured to quarantine or reject for full protection.
Even if your domain isn't on a public blacklist (or blocklist), private blocklists maintained by Microsoft can still impact deliverability. These internal lists are often based on real-time feedback and behavioral data, making them harder to diagnose without direct insight. For a comprehensive overview of blocklists, refer to our in-depth guide to email blocklists.
Authentication checklist
SPF record: Ensure your SPF record is correctly set up to authorize all your sending IPs and domains. Incorrect setup or too many lookups can cause issues.
DKIM signature: Verify that your emails are consistently signed with a valid DKIM signature. A missing or invalid DKIM signature is a major red flag for spam filters.
DMARC policy: Implement a DMARC policy (at least at p=none) to monitor your email authentication. This helps you gain visibility into how your emails are being authenticated and identify potential spoofing attempts. Our free DMARC record generator tool can help you create one.
Content and engagement signals
While good click-to-open rates indicate that the emails reaching the inbox are engaging, other content and engagement factors can still trigger spam filters for the remainder of your sends. Microsoft's filters are highly sensitive to content that might appear spammy or inconsistent with typical user behavior. This includes excessive use of promotional language, certain keywords, or even overly large images and attachments. It's not just what you say, but how you say it, and how your emails are structured.
Beyond explicit clicks and opens, Microsoft also monitors subtle engagement cues. Do recipients reply to your emails? Do they move them to specific folders? Do they add your address to their address book? A lack of these positive engagements, coupled with any negative signals like spam complaints (even if low in number), can degrade your sender score over time. Outlook's spam filter settings frequently adapt to user preferences and actions.
Another factor is the type of content you are sending. If you're sending transactional emails, the expectation for engagement is different from marketing newsletters. Microsoft's algorithms are adept at distinguishing between these types and will apply different filtering criteria. Ensure your email content aligns with recipient expectations to avoid being flagged as spam. Understanding the underlying reasons for low deliverability with Hotmail and Outlook is crucial.
Positive signals
Opens and clicks: High rates indicate interest, but can mask underlying inbox placement issues.
Replies: When recipients respond to your emails, it's a strong positive indicator to filters.
Moving to inbox: If emails are moved from junk to inbox, it teaches the filter to trust your sender.
Adding to contacts: Adding your address to a contact list signals trust and preference.
Negative signals
Spam complaints: Even a small number can significantly damage your sender reputation.
Low engagement: Recipients deleting without opening, or ignoring your emails, sends a negative signal.
Inactive addresses: Sending to unengaged or inactive addresses increases the risk of hitting spam traps.
Content issues: Spammy language, broken links, or misleading subject lines can trigger filters.
Hidden technical and behavioral factors
Sometimes, the problem isn't obvious reputation or authentication, but subtle technical configurations. For instance, where your images are hosted. If your emails use images hosted on a Content Delivery Network (CDN) that has a poor reputation, or if the CDN itself is associated with questionable domains, this can impact your emails' standing with Microsoft filters. Even if your main sending domain is pristine, auxiliary domains can become a weak link.
Another often overlooked aspect is the quality of your subscriber list. Sending to a list that contains many inactive or disengaged users can dilute your overall engagement rates and lead to more negative signals over time, even if a core segment is highly engaged. Microsoft, like other major providers, heavily weighs subscriber engagement. Low engagement can lead to emails being sent to the junk folder, as detailed in various articles on why emails go to spam.
Furthermore, Microsoft may employ machine-learning based customer-value testing. This means their systems might experiment with delivering a portion of your emails to the junk folder to see how recipients react. If users consistently retrieve these emails from junk, it could improve future deliverability. However, if they are left in junk or marked as spam, it reinforces the negative filtering. This dynamic makes diagnosing issues particularly challenging, as it can feel like your deliverability is subject to factors outside your direct control. When your emails are landing in Office 365 spam folders, a deep dive into these nuanced factors is often required.
Views from the trenches
Best practices
Maintain pristine list hygiene by regularly removing inactive or unengaged subscribers to prevent hitting spam traps.
Consistently monitor your email authentication records (SPF, DKIM, DMARC) for proper configuration and alignment.
Encourage positive recipient actions, such as adding your email to their contact list or moving emails from junk to inbox.
Segment your audience based on engagement levels to tailor content and sending frequency, improving overall sender reputation.
Common pitfalls
Assuming good click-to-open rates equate to perfect inbox placement across all providers, especially Microsoft.
Neglecting the reputation of third-party hosted content, like images on CDNs, which can affect overall deliverability.
Ignoring subtle negative signals from Microsoft, such as a drop-off in total reach not explained by bounces.
Failing to adapt to evolving sender requirements from major mailbox providers like Microsoft and Yahoo.
Expert tips
Implement DMARC reporting to gain deeper insights into your email authentication status and identify potential issues.
Diversify your sending strategy if you notice persistent deliverability issues with a specific provider like Microsoft.
Analyze engagement trends not just by open rates, but by total delivered volume vs. actual inbox placement.
Consider the broader context of user behavior changes, such as shifts in how people access email during specific periods.
Expert view
Expert from Email Geeks says: The spam folder should not be considered binary; some emails will still reach the inbox even if others are filtered.
2020-03-24 - Email Geeks
Expert view
Expert from Email Geeks says: Consistent click-to-open rates paired with a drop in overall volume can indicate that a fraction of mail is going to the spam folder.
2020-03-24 - Email Geeks
Bringing it all together
When your emails consistently land in the Hotmail or Microsoft spam folder despite good click-to-open rates, it’s a clear sign that you need to look beyond surface-level metrics. The issue likely stems from a combination of sender reputation, authentication failures, negative engagement signals, or hidden technical factors.
Addressing this requires a holistic approach, focusing on robust email authentication, maintaining a clean and engaged subscriber list, optimizing email content for Microsoft's filters, and consistent monitoring of your deliverability across all providers. By taking these steps, you can significantly improve your email deliverability with Microsoft Outlook and Hotmail and ensure your messages reach their intended destination.
Microsoft. Your reputation is influenced by various factors, including spam complaints, bounce rates, and overall engagement patterns, not just clicks.
