Create Unengaged Customers Segment in Omnisend

Why Unengaged Customers Hurt Your Email Marketing Performance

You send a campaign. Open rates are lower than expected. Your inbox placement tool flags spikes in spam complaints. You check your list—only to find thousands of inactive subscribers buried in the mix.

Inactive users don’t just sit quietly. They skew your metrics, degrade sender reputation, and increase the odds of your messages landing in spam folders or bouncing outright. You’re not just wasting sends—you’re risking long-term deliverability.

How to create an unengaged customers segment in Omnisend? Start by recognizing that unengaged subscribers aren’t just inactive—they’re actively harming your email performance. This guide walks through creating that segment precisely, based on real engagement data, so you can exclude them from future sends and improve overall campaign results.

Key takeaways

Unengaged customers reduce campaign performance metrics like open and click rates, making it harder to measure real success.
Sending to inactive users increases the risk of spam traps and sender reputation damage, especially when combined with high bounce rates.
Creating a dedicated unengaged customers segment in Omnisend lets you suppress these contacts, improving deliverability and reducing wasted sends.

What Does 'Not Opened in 6 Months' Really Mean in Omnisend?

When you use Omnisend’s "not opened in 6 months" filter, you’re targeting subscribers who haven’t opened, clicked, or engaged with any campaign in the past 180 days—regardless of earlier activity. It’s not a low-engagement signal; it’s a hard exclusion threshold for true inactivity. This metric helps identify users disconnected from your brand, allowing automated workflows to remove them from active campaigns.

It’s Not About Past Activity—It’s About Recent Silence

Past engagement doesn’t count here. If a subscriber opened a campaign two years ago but hasn’t interacted in the last six months, they still qualify. Omnisend tracks only open and click activity over the last 180 days, so this filter ignores long-ago interactions. That means even previously active users get flagged if they’ve gone quiet.

Let’s be clear: this filter doesn’t measure “low interest.” It measures “no interaction.” This distinction is important when building your segmentation strategy. Using it helps you avoid sending content to lists where engagement has flatlined. According to industry benchmarks, email lists with high inactive segments often see deliverability issues—senders with over 25% inactive users report higher bounce and spam complaints.

How This Drives Automation

Many brands use this segment to trigger automated exclusions. For example, you can set a workflow to remove users from your active list after six months of non-open. This reduces clutter, improves sender reputation, and keeps your list healthy.

But there’s a risk: if you exclude users too aggressively, you might lose opportunities to re-engage. That’s why we recommend pairing this filter with re-engagement campaigns before full exclusion. Use the segment to trigger a targeted “We miss you” campaign before pulling them from your main list. This approach balances list hygiene with recovery.

Healthy list management starts with clean data. If you’re building segments based on behavior, ensure your subscriber data reflects actual engagement—not outdated or invalid email addresses. You can verify list accuracy at scale with Email List Validation’s bulk verification tool, which identifies invalid, disposable, or catch-all emails before they impact your campaigns.

Tools like Omnisend rely on clean, active data. The “not opened in 6 months” filter works best when only real, deliverable emails are in the list. Confirming email validity up front—especially in bulk—helps ensure your segments reflect behavior, not noise. For real-time checks, use the verification API during sign-up or list uploads.

How to Create an Unengaged Customers Segment in Omnisend Using Filters

You can create an unengaged customers segment in Omnisend by going to the Segments tab, clicking Create Segment, selecting 'Contacts who have not opened any campaign in the last 180 days', naming it (e.g., 'Inactive Subscribers - 6 Months'), and saving. This helps you identify subscribers who haven’t interacted in six months, allowing you to re-engage them or remove them to improve deliverability and sender reputation.

Log in to your Omnisend dashboard and navigate to the Segments tab in the left-hand menu. This is where you manage all customer groups based on behavior, demographics, or activity.
Click Create Segment and choose Based on activity. This option lets you define segments using behavioral data like opens, clicks, and purchases, which is the most accurate way to identify inactive users.
Select the filter: Contacts who have not opened any campaign in the last 180 days. This rule targets users who haven’t opened a single email in half a year — a strong signal of disengagement. Studies from industry reports suggest that subscribers inactive for over 180 days are likely to be uninterested or have outdated email addresses.
Name your segment clearly — for example, ‘Inactive Subscribers - 6 Months’ — so you can easily recognize it later in campaigns. Clear naming avoids confusion during segmentation audits.
Save the segment. It will automatically update as new data comes in, ensuring you’re always working with current inactive users.

Why This Filter Works

Emails sent to unengaged users can hurt your sender reputation. ISPs track engagement patterns, and sustained inactivity may lead to inbox placement issues. According to data from Return Path and major email providers, consistent low engagement correlates with higher spam filtering rates.

Next Steps

Once you have the segment, consider re-engagement campaigns with compelling offers. If response remains low after 2–3 emails, consider removing them. Maintaining a clean list improves deliverability and ensures your messages reach active subscribers.

If you’re managing large lists, validating your contacts upfront reduces the risk of unengaged records. Use bulk email list cleaning or real-time verification to catch invalid or risky addresses before they enter your list. For better targeting, try the email finder to identify leads. All tools support seamless integration with Omnisend via available integrations. Start with 100 free verifications and see immediate value.

How Email List Validation Improves Segment Accuracy Before You Segment

You can't reliably identify unengaged customers if your list contains invalid, catch-all, or disposable emails. These addresses create false inactivity signals because they never reach the inbox, skewing your segmenting logic. Clean your list first with real-time verification to ensure every address is valid and deliverable before applying any engagement filters.

Why Invalid Emails Distort Engagement Signals

When you filter for inactive subscribers, you're assuming every email in your list gets a real chance to be seen. But if even 5% of your addresses are undeliverable—due to typos, outdated domains, or catch-alls—the system treats them as inactive simply because no delivery ever happened. That’s not disengagement; it’s undeliverability. This inflates your inactive segment, wasting time and resources on people who were never reachable.

For example, a catch-all email address may accept messages but never route them to a real user, meaning no open or click can occur. Similarly, disposable domains (like tempmail.org) are often used for signups that never result in real interaction, yet they still count as “active” in a raw list. These fake signals mislead segmentation logic and undermine campaign performance.

Verification First: The Real Foundation of Accurate Segmentation

Let’s be clear: your segmentation is only as good as your source data. A 98.9% accurate email-verification tool ensures only real, deliverable addresses remain in your list. This means no false negatives, no wasted sends, and no misleading reports. You’re not just trimming dead weight—you’re building a clean data foundation for all your marketing decisions.

With tools like bulk verification or the real-time API, you can validate entire lists in seconds, flag risky addresses, and remove them before they ever touch your automation rules. The result? Your “inactive” segment reflects actual user behavior—not undeliverable noise.

Industry standards like RFC 5321 and best practices from providers like Spamhaus emphasize proper validation as a key part of email hygiene. Skipping it means you’re operating on assumptions. The cost? Wasted campaigns, poor inbox placement, and a deteriorating sender reputation.

How to Clean Your List with Email List Validation Before Creating Segments

You can create a truly unengaged customers segment in Omnisend only after cleaning your list. Use Email List Validation to remove invalid, catch-all, and risky addresses before segmentation. This stops bounces, protects sender reputation, and improves inbox placement—critical for deliverability. Real-time API checks during sign-up prevent bad data from ever entering your list.

Step 1: Upload your list for bulk verification

Start by uploading your email list to Email List Validation. The platform checks each address against SMTP, MX, and domain-level rules in real time. This includes identifying invalid syntax, non-existent domains, and catch-all setups that may appear valid but don’t deliver. You’ll get back a detailed report with clear verdicts: valid, invalid, catch-all, or risky.

Learn more about bulk verification.

Integrate the Email List Validation API into your website or app’s signup form. It validates addresses instantly—before you store or send to them. This stops fake or typo-ridden emails from entering your database. It’s an industry-standard practice to verify at the source, reducing long-term list decay and keeping deliverability metrics stable.

See how the API integrates with your workflow.

Step 3: Review verification results and filter clean data

After validation, you’ll see four labels: valid, invalid, catch-all, and risky. Invalid addresses are confirmed undeliverable. Catch-all accounts accept any email—meaning the address is syntactically valid, but messages may never reach the intended recipient. These should be removed. Risky addresses may have issues like throttling or greylisting. They’re not outright invalid, but they pose delivery risk.

According to RFC 5321, SMTP servers expect valid MX records and reachable end points. Addresses without them are not reliable for bulk messaging.

Step 4: Remove invalid and catch-all addresses before segmenting

Only use addresses marked as valid when creating your unengaged customers segment in Omnisend. Do not include catch-all or invalid entries. If you include them, you’ll increase bounce rates, which can trigger spam filters and hurt sender reputation. High bounce rates are a red flag to email providers like Gmail and Outlook.

Sync the cleaned list directly with Omnisend to build accurate, high-performing segments.

Why 'Catch-All' and 'Risky' Addresses Skew Engagement Data

Invalid emails — especially catch-all domains and risky addresses — mimic engagement by appearing to receive messages, but they’re not real users. This leads to misleading data: your 'inactive' list might actually be full of fake or broken addresses, making engagement metrics unreliable. Cleaning these out first gives you an accurate picture of real customer behavior.

Catch-All Domains Create False Positives

Catch-all domains accept any email sent to them, even invalid ones. The email appears delivered, but the recipient never sees it. This inflates your open and delivery rates artificially, making your campaigns look better than they are. If you’re building an unengaged segment in Omnisend, these addresses falsely get labeled as inactive because they don’t respond — but that’s not because they’re uninterested. It’s because the address doesn’t exist.

According to the IETF’s RFC 5321, catch-all behavior is technically valid but not advised, as it enables spam abuse and wastes bandwidth. Some providers still use it, but it’s not a signal of a real user. If your list includes such addresses, your automation and segmentation are working on noise, not real people.

Risky Addresses Are Usually Not Real Users

Risky emails often belong to role accounts (like sales@ or info@), free providers with high bounce rates, or known spam traps. These don’t represent real customers. Even if they “deliver” (which they might not, due to greylisting or filtering), there’s no meaningful engagement. Let’s be clear: the lack of interaction isn’t disengagement. It’s a symptom of invalidity.

Risk score algorithms detect these patterns — they're common in poor-quality lists. If you're segmenting based on non-response, you’re including people who never received the message in the first place. This corrupts your view of customer health and leads to bad decisions: over-segmentation, wasted sends, or poor timing for re-engagement campaigns.

Use email verification to filter these out before sending. Tools like bulk email list cleaning or the real-time API can flag catch-all and risky addresses with high precision. This ensures your "unengaged" segment truly reflects customers who once responded and now haven’t — not people who never existed. Only then can your Omnisend segments reflect actual customer behavior.

Use Inbox-Placement Testing to Confirm Deliverability Before Segmenting

Before you create an unengaged customers segment in Omnisend, run a real-world inbox-placement test to confirm your emails are landing in inboxes—not spam folders or being blocked entirely. This step prevents wasted effort and protects your sender reputation. If your emails aren’t reaching inboxes consistently, segmenting won’t help—your messages won’t be seen at all.

Test Deliverability First

Send a test campaign through Email List Validation’s inbox-placement tool. This simulates how your email will behave across real inbox providers like Gmail, Outlook, and Yahoo. It checks not just delivery, but whether your message is marked as spam or rejected.
Review results across providers. You'll see exact delivery rates per inbox provider. If deliverability is below 90% for any major provider, your sending infrastructure may need tuning—especially SPF, DKIM, or DMARC alignment.
Check bounce and spam feedback loops. The test includes insight into whether your message is being flagged by spam filters or rejected based on reputation. If you're hitting 30% or more spam placement in Gmail or Yahoo, your sender reputation is compromised.
Only proceed with segmentation after confirmation. If your test shows consistent inbox delivery across providers, you can proceed with confidence to identify unengaged customers in Omnisend using open/click thresholds.

Why This Step Matters

Even a perfectly segmented list fails if emails don't land in inboxes. According to industry data from MxToolbox, over 50% of emails from new senders end up in spam folders due to poor deliverability practices. A single low deliverability score can sink an entire campaign—especially when trying to re-engage users.

The 4 steps described in “Test Deliverability First”, in order.

Testing before segmentation avoids wasted effort. You're not just filtering inactive users—you're ensuring your message has the chance to be seen. If your deliverability is weak, fix the root cause: check your domain reputation with tools from MxToolbox, verify your authentication setup, and monitor blocklists.

Once you're confident your emails land in the inbox, use the inbox-placement feature to validate each new list or campaign before sending. This reduces bounce rates and builds long-term sender health.

How to Integrate Email List Validation with Omnisend

You can integrate Email List Validation with Omnisend in under five minutes using OAuth. Once linked, every new subscriber or imported list is automatically validated in real time—preventing invalid, disposable, or inactive emails from entering your main contact list. This keeps your sender reputation strong, reduces bounces, and improves inbox placement. For context, the average deliverability rate drops by 15% when more than 2% of your list is invalid.

Set up your integration

Go to the Email List Validation integrations dashboard and select Omnisend from the list of supported tools.
Click “Connect” and follow the OAuth flow to authorize Email List Validation to access your Omnisend account.
Choose the specific contact lists you want to sync with validation—either all lists or specific segments like new subscribers.

Enable real-time validation

Turn on automatic validation for new imports or subscriber uploads. This runs checks against SMTP servers, MX records, and known disposable domains before any email reaches Omnisend.
Set rules to block catch-all, role-based, or disposable emails. For example, emails like admin@, sales@, or temporary domains like mailinator.com are filtered out.
Confirm that validation runs on every sync. Your Omnisend list stays clean by default—no manual cleanup needed.

Why this matters: Email addresses that don’t resolve or belong to non-existent inboxes cause hard bounces, which harm your sender reputation over time. According to Spamhaus, repeated soft and hard bounces correlate with email domain blacklists. By catching issues before they hit your list, you’re defending your deliverability.

For broader cleanup, use the bulk verification feature on your existing contacts. It checks the full list at once and returns a detailed report—valid, invalid, risky, catch-all—so you can segment and suppress with precision.

You’re not just maintaining a clean list—you’re actively protecting your engagement metrics. Inactive contacts aren’t just unengaged; they’re a delivery risk. Validating before subscription is smarter than filtering after the fact.

Key Differences Between Omnisend's 'Inactive' Filter and List Hygiene Tools

You can’t trust Omnisend’s 'inactive' filter alone to identify truly disengaged customers—its only measure is lack of opens, which ignores undeliverable, disposable, or risky emails. That means your inactive segment may include bounced addresses, fake accounts, or outdated data. Cleaning your list first with a tool like Email List Validation ensures that every email in your 'inactive' segment has actually been delivered and is valid—because you’re not sending to dead addresses to begin with.

How Omnisend’s Inactivity Filter Works

Omnisend’s 'inactive' filter marks users who haven’t opened an email in a set time window—commonly 30, 60, or 90 days. It assumes the email is valid and deliverable. If a user's address is mistyped, blocked, or belongs to a disposable domain, Omnisend still counts them as inactive after the first failed delivery. This leads to false negatives: you’re treating non-opens as disengagement when the email never even arrived.

Why List Hygiene Precedes Segmentation

Before labeling anyone inactive, you need to confirm their address is valid and capable of receiving mail. Tools like Email List Validation check for syntax errors, domain validity, catch-all setups, and disposable domains using real-time SMTP verification. They also detect role-based addresses (like admin@ or sales@) that often degrade sender reputation over time. A clean list means your inactivity data reflects real user behavior—not failed deliveries.

For example, a study by Return Path found that up to 20% of email lists contain hard bounces or invalid addresses. Without hygiene, these distort engagement metrics and waste sender reputation. The fix isn’t more segmentation—it’s better data prep.

Use Email List Validation to clean your list before using any segment filter in Omnisend. You’ll reduce bounce rates, improve inbox placement, and avoid sending to addresses that aren’t even real. Check out the [bulk verification feature] to start with a clean list at scale.

Combine Both for True Engagement Insights

Run list hygiene first. Then, apply Omnisend’s 'inactive' filter on the cleaned list. Now, every user in that segment has actively opted in, received mail, and stopped engaging. That’s the real definition of unengaged. You’re not guessing. You’re acting on data that’s accurate, deliverable, and meaningful.

What to Do With Your Unengaged Customers Segment

You should exclude inactive subscribers from future campaigns to protect your sender reputation and improve open and click rates. Then, run a win-back campaign with compelling subject lines and personalized content—this works for many brands. If there’s no response after 2–3 emails, suppress the segment or remove it entirely to maintain list hygiene. This approach keeps your metrics healthy and your deliverability strong.

Immediate Actions: Protect Your List Health

Exclude unengaged users from standard campaigns. Sending to inactive subscribers inflates bounce rates and harms deliverability—industry best practices (like those from Return Path’s inbox placement research) show that clean lists perform better over time.
Use Omnisend’s segmentation tools to define inactivity based on open and click thresholds (e.g., no engagement in 90 days). Define this rule clearly to prevent manual errors.
Before any win-back send, verify your list with an email verification tool. Invalid, expired, or malformed addresses can trigger bounces and hurt your sender reputation—run a bulk verification to clean your list first. Bulk email list cleaning removes risks before you send.

Win-Back Sequence: Re-engage or Let Go

Send a clear, high-value win-back email with a subject line that stands out—focus on relevance, not hype. Avoid generic terms like “We miss you”; use the customer’s name and reference past behavior instead.
Include a single strong call-to-action: a discount, exclusive content, or a re-engagement survey. Too many choices reduce conversion.
If no opens or clicks occur after 2–3 sequential emails, suppress the segment in Omnisend. This prevents future sends and protects sender reputation. Some platforms allow permanent suppression; others may require removal after a set period.
Consider whether removing users entirely is necessary. For high-value segments (e.g., past buyers), you can re-engage later after a longer pause—but never re-engage without list hygiene first.

“Maintaining a clean email list is not a one-time task—it’s a continuous discipline.” Return Path research supports that sustained low engagement correlates with higher inbox placement risk.

Let’s be clear: chasing every inactive user is inefficient. Focus your energy on those who still respond. Use tools like real-time email verification API to catch bad addresses before they reach your inbox. Your deliverability depends on it.

The Long-Term Impact of Poor List Hygiene on Deliverability

Every invalid address in your list increases your bounce rate. High bounce rates signal poor list quality to inbox providers, which can hurt your sender reputation over time.

Red Flags in Your List

Spam traps are inactive addresses used to identify spammers — sending to them risks blacklisting.
Catch-all domains accept any email address, often used by bots or disposable services, and indicate low-quality data.
Disposable emails are temporary — users won’t engage, and their presence inflates bounce metrics without benefit.

Even perfectly crafted messages get filtered if your list contains these signals. Proactive email validation prevents degradation of inbox placement over time.

Sources

Segmented email campaigns earn 14.31% higher open rates and 100.95% higher click rates than non-segmented campaigns. — Mailchimp (2025)

Keep reading

Ready to put this into practice? Email List Validation verifies emails with 98.9% accuracy — start with 100 free verifications.

Frequently asked questions

How do I create an unengaged customers segment in Omnisend?

In Omnisend, go to Segments > Create Segment > Choose 'Contacts who have not opened any campaign in the last 180 days'. Name the segment and save it.

What does 'not opened 6 months' mean in Omnisend?

It means a subscriber hasn’t opened any campaign sent by your account in the past 180 days, indicating disengagement.

Can I use Email List Validation with Omnisend?

Yes. Email List Validation integrates with Omnisend to enable real-time and bulk email verification before list imports.

Why is list hygiene important before creating inactive segments?

Invalid or catch-all emails can incorrectly appear inactive. Cleaning your list ensures your segment reflects true disengagement.

What’s the difference between catch-all and invalid emails?

Catch-all domains accept all emails — even invalid ones. Invalid emails belong to non-existent or inactive accounts.

How often should I clean my email list?

At minimum, clean your list before each major campaign. Use tools like Email List Validation for ongoing maintenance.

Does removing inactive subscribers improve deliverability?

Yes. Lower bounce rates and fewer spam trap hits help maintain a strong sender reputation, improving inbox placement.

Can I re-engage inactive subscribers?

Yes. Run a targeted win-back campaign with compelling content. If no response, suppress the list to avoid damage.

What happens if I don’t clean my list?

Your bounce rate rises, sender reputation drops, and emails are more likely to land in spam or be blocked.

Does Email List Validation offer free verifications?

Yes. Start with 100 free verifications. Purchased credits never expire, so they can be used over time.

How accurate is Email List Validation?

It has a 98.9% accuracy rate in identifying valid, invalid, catch-all, and risky email addresses.

Is Omnisend’s inactive filter reliable on its own?

It’s useful, but not reliable without prior list hygiene. It may include invalid or catch-all emails, skewing results.