NetSuite Tips – How to Maintain a Clean Mailing List (Updated for 2026)

The world of digital marketing is always changing and evolving, but one thing that stays steady is the importance of email marketing. In 2026, 22% of marketers report email as one of their top ROI-driving channels, meaning that when you get it right, it really delivers.

NetSuite can help you make your email marketing strategy easier to implement and maintain. However, there are steps you can take to make it more successful so it drives bigger results. And a large part of that is maintaining a clean mailing list – including keeping your hard bounce rate low.

If email marketing is part of your marketing strategy, you need to be maintaining your mailing list – but what does this entail? How often should you be ‘cleaning’ it?

In this post, we’ll answer these questions more, to help you ensure you get the most out of your email marketing strategy and get the most benefits from NetSuite to support it.

What Does ‘Cleaning Your Mailing List’ Mean?

Email marketing campaigns run using a list of emails you wish to contact. Cleaning this list means removing any unengaged, invalid or duplicated email addresses to keep the quality of that mailing list high.

The higher the quality of your mailing list, the better opening rate you’ll gate, the more conversions you’ll win, and the bigger ROI you’ll see. This makes it a worthwhile task for any business that uses email marketing.

Who should you target when cleaning your mailing list?

When you’re cleaning your mailing list, you need to look out for four types of subscribers to remove:

• Unsubscribed email addresses: In some instances, this will be a legal duty in line with GDPR and other regulations. If someone has clicked the ‘unsubscribe link’ in your email, they need to be removed from your list within a set time (aim for within 10 days).
• Invalid email addresses: If an email address doesn’t exist, obviously, it can’t receive emails. The reasons an email might be invalid vary, from it being misspelled when it was entered, though to a defunct email provider or the user closing the account. Either way, leaving them on your list will damage your sender reputation so you should delete them if and when you can.
• Duplicate addresses: Sending the same email, multiple times to the same address annoys subscribers and can lead to email providers marking your emails as spam. Removing duplicate emails as part of your cleaning process removes these issues.
• Unengaged or inactive subscribers: Even people who choose to sign up to your email list may not follow the links in your emails – some won’t even open them at all. These are unengaged subscribers and having a long list of these can lower your sender reputation.

Regularly cleaning your mailing list is vital to protect your sender reputation. If you don’t, you can end up with a lot of bounced emails which damage your reputation and lead email service providers to class you as spam.

What Is a Bounced Email? 

When an email fails to deliver, it ‘bounces’. This can happen for a number of reasons – some are temporary, known as a ‘soft bounce’, but if the issue is permanent then this results in a ‘hard bounce’.

Possible reasons for hard bounces: 

• Unknown User 
• Bad Domain 
• Address Error 
• Account Closed 

Possible reasons for soft bounces: 

• Mailbox Full 
• Disabled Account 
• Greylisted 
• Server Too Busy 

How Does NetSuite Manage Bounced Emails? 

In NetSuite, when an email message returns an invalid address or hard bounce, any records associated with that email address offer a warning that the email address is invalid. 

This includes: 

• Email campaigns 
• Customer, contact, vendor, employee, and other name records 
• Email messages 

These email addresses are also added to the ‘Bounced Email Address List’.  

NetSuite will not send email messages to addresses that have triggered a hard bounce until they are removed from this list, either manually or after a specified time has elapsed.  

(This specified time is set by the account administrator under the Email tab in Setup > Company > Preferences > Set Up Printing, Fax & E-mail.) 

You can view a list of bounced email addresses at Lists > Relationships > Bounced Email Addresses.

Here, you can manually remove email addresses from the list to include them in email campaigns once again. 

As long as email addresses are present on this list, then NetSuite won’t send these recipients emails. However, they only stay on this list for the defined period of time mentioned above. The defined periods of time to “Remove Email Addresses from the Bounced Email Address List After” are 30 days, 90 days, 180 days or never: 

If your account is set to ‘never’, then bounced emails will stay on this list and, therefore, never be sent unless you manually remove them.  

Tip: You may still incur a charge for these messages, so you need to set “Hard Bounced is false” as a criterion when setting up your recipient groups.  

If your defined time is anything other than ‘never’ then they will be removed from the list, and therefore NetSuite will once again try to send emails to them.  

In addition to keeping track of hard-bounced email addresses resulting from email marketing campaigns and mail merges, Netsuite tracks any address that has been hard-bounced from any email sent from NetSuite including transactional email. 

Should I remove hard bounced email addresses from mailing lists?

Yes, you should be regularly checking your bounced email list and unsubscribing hard bounce addresses. Otherwise, if they get removed from your ‘Bounced Email Address List’, NetSuite will start sending emails to them again.

This becomes a real issue if you set the timescale of your automated ‘Remove Email Addresses from the Bounced Email Address List after’ to anything less than ‘never’.

Removing hard bounces is an important part of cleaning up your mailing list. Here’s how you can do it:

How to remove a bounced email address from your list

1. Navigate to the Bounced Email Address List at Lists > Relationships > Bounced Email Addresses. 
2. Tick the box in the Delete column for each email address you want to clear the bounce history for or click Mark All to select all email addresses in the list. 
3. Click Delete. 

Their bounce history will then be removed, and you can continue to email them. 

If you have checked your Bounced Email Address List and you’re happy that there’s no one on there who should be receiving your email campaigns, then you can manually go into each recipient’s record and unsubscribe them. This means that they will never receive emails from you again and will therefore stop triggering a hard bounce. 

Alternatively, if there are a number of email addresses that you wish to unsubscribe, then you can perform a mass update (see below). 

What emails should I not delete?

Even if an email has ‘hard bounced’ this doesn’t mean you should definitely delete it. Sometimes, when you check the address you’ll still want to contact. You might find the address was typed incorrectly, or that the format of the company email has changed but you still want to contact that person.

This is why manually cleaning your mailing is such an important part of maintaining it.

Mass unsubscribing entities with bounced email addresses 

You can unsubscribe customers and others with invalid email addresses from email campaigns with a mass update. This mass update can be based on the ‘Hard Bounced’ field that is set on a record whenever an email sent from NetSuite triggers a hard bounce. 

1. Go to Campaigns > Other > Mass Updates.
2. Expand ‘General Updates’.
   
3. Click the type of record you want to unsubscribe
4. On the Mass Update page, on the Criteria subtab, select ‘Hard Bounced’ in the Filter column. Choose ‘yes’ to select all those recipients whose email addresses have hard bounced
5. Click Set
6. Enter any other criteria for the records you want to unsubscribe
7. Click the Mass Update Fields subtab
8. Tick the box in the Apply column next to Global Subscription Status box
9. In the Value column, select ‘Soft Opt-Out’
10. Click Preview to review the records that will be affected by this update
11. On the preview page, click Perform Update