Note: If you're a Legacy (Classic) user, please log in to your account to access the dedicated Legacy (Classic) Help Center.
Migrating from MailerLite Legacy (Classic) to New MailerLite is a seamless process, but occasionally, unexpected issues may arise. This troubleshooting guide is here to help you address common migration hiccups and find solutions. Please review the following troubleshooting steps for a smooth transition:
Troubleshooting failed migration
Missing content
1. If you notice that some content is missing during your migration, give it another try by resetting the migration steps. Detailed instructions on how to reset the migration process can be found in this article.
2. Certain assets created with older editors cannot be migrated. If you find that content is still missing after resetting your migration, it's likely due to these older assets. In such cases, you may need to re-create the missing content in the new MailerLite.
Migration process still in progress
If your migration process is still in progress and loading, please be patient and avoid attempting to reset it, as it might take a bit longer to complete.
Troubleshooting campaign migration
Campaigns are not being migrated
Keep in mind that email templates, drafts, and sent campaigns are migrated at separate steps of the migration process. Campaigns in Outbox are not migrated.
Additionally, some campaigns created with older editors cannot be migrated.
What happens with preview links from Legacy (Classic) campaigns
On February 1st, 2026, the preview links from previous campaigns created in MailerLite Legacy (Classic) have been deactivated. This means that any existing preview links you may have had will no longer be accessible or functional.
Troubleshooting templates post Free trial
After your free trial period ends in the new MailerLite, you may notice that templates cannot be edited. However, they can still be used in your campaigns. Here's what you need to know:
Template editing limitation
Templates become uneditable once your free trial ends. This means any customizations or changes to the template are restricted unless you upgrade to a paid plan.
Using templates in Campaigns
While you can't modify templates after the trial, you can still utilize them in your campaigns without any issues. They remain a valuable resource for creating consistent and visually appealing email content.
Troubleshooting subscriber migration
Migrating more than 250 subscribers
If you have more than 250 subscribers in Legacy (Classic) and are on a free plan in the new MailerLite, you can migrate only 250 subscribers by selecting the groups of your choice. That said, if you enable Loyalty Trial, you will be able to import your whole list!
Alternatively, you have the option to either upgrade your plan to accommodate all your subscribers or export the remaining ones.
Re-syncing subscribers
If you continue to receive subscribers in Legacy (Classic) after the migration, you can re-sync them by following the steps provided here.
If you choose not to upgrade your Legacy (Classic) account, you won't be able to re-sync subscribers. To address this, we recommend migrating your forms to the new MailerLite and updating the JavaScript or HTML code used to embed them on your websites. This step ensures that new subscribers are seamlessly added to your new MailerLite account, allowing you to maintain a streamlined subscription process.
To make changes to your templates or unlock advanced features, consider upgrading to one of our paid plans. This will provide you with greater flexibility and customization options for your email campaigns.
Troubleshooting automation migration
If you want to learn how to migrate automations, you can find guidance here.
Some automation emails were not migrated
Certain assets created with older editors cannot be migrated. If you find that emails are still missing after resetting your migration, it's likely that these emails were originally created using an older editor. In such cases, you may need to re-create the missing emails in the new MailerLite.
Automations are not active
Once your automations are migrated, you will need to activate them manually. You can do this in the automation editor, where you’ll also be able to sync your queued subscribers to make sure they continue the automation where they left off in Legacy (Classic).
Automation activity and history were not migrated
Past automation activity such as completed, failed, and canceled subscribers is not synced. As your subscribers continue to move through the automation, new activity will be registered.
Since automation history is not migrated, if you need to recover any past changes to the automation, make sure to redo them manually instead of restoring.
Keeping subscribers historical data
Missing subscriber data and sent campaigns
Keep in mind that subscriber data and sent campaigns from the past 12 months are migrated.
If you’d like to preserve older data, you can:
Export your subscriber list. The exported file will include statistics such as the number of sent emails to this subscriber, clicks, and opens. You can import this data to custom fields in New MailerLite or keep the file on your device for future reference.
Download campaign reports. In the Campaigns page of your Legacy (Classic) account, mark the checkbox to Select all campaigns and click Download reports. This way you can keep a record of the key stats of your past campaigns.
Copy sent campaigns to convert them to drafts. If you wish to keep the designs of your sent campaigns, copying them will add a duplicate version to the Drafts section. You can then sync drafts to your new account.