Thunderbird Sending Duplicate Emails – Fixed

Rollins Duke   
Published: October 23rd, 2023 • 7 Min Read

You are here because your Thunderbird sending duplicate emails. You want to learn how to stop duplicate emails in Thunderbird. Then stay tuned with this write-up to know the reasons behind this problem and effective ways to fix Thunderbird’s double emails sent and received problem.

Nowadays millions of computer users use Thunderbird to send and receive emails. Thunderbird is an open-source email client which is available to use free of cost. Even Thunderbird’s easy-to-use graphical user interface and world-class security features force users to use it.

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How Do I Stop Duplicate Emails in Thunderbird?

Hi BitRecover Support, I am sending this email because I am facing a critical issue in Thunderbird. I am using the Thunderbird email client to manage email and contact information. But due to a possible virus attack or other reason, my Thunderbird receiving duplicate emails. Even later after a few days, my Thunderbird started sending duplicate emails. But I don’t know how to stop duplicate emails in Thunderbird, please suggest me a solution to resolve my problem.

– Colton Smith, Florida

Steps to Fix Thunderbird Sending Duplicate Emails

  1. Install, and run BitRecover Tool.
  2. Add Thunderbird profile data in GUI.
  3. Select specific Thunderbird mailboxes.
  4. Enable a mode and advance filters.
  5. Click Extract to fix clutters.

Note That: You can complete the steps mentioned above if your Thunderbird is sending duplicate emails. But before using this software, please ensure you are using the correct Thunderbird account settings. If you use the wrong account settings, then your Thunderbird may again send and receive duplicate emails. Let’s continue to read this article and get complete information about the problem.

Recommended: Best Techniques to Speed Up Thunderbird

Why Does Thunderbird Send Emails Twice?

Thunderbird may send duplicate emails for several reasons. Some common causes include:

  • Server Sync Issues: Inaccurate synchronization with the email server can result in Thunderbird downloading and sending duplicate emails. This can happen if the server’s message UID (unique identifier) changes unexpectedly.
  • IMAP Folder Corruption: Corruption in IMAP folders on the server or locally in Thunderbird can cause synchronization problems. Hence, Thunderbird may send and receive emails twice.
  • Email Rules and Filters: Misconfigured email rules or filters in Thunderbird can inadvertently trigger the sending of duplicate emails. Check your Thunderbird rule settings to ensure they’re correctly applied.
  • Multiple Account Configurations: If you have configured multiple email accounts in Thunderbird. Then mismanagement of these accounts, such as sending emails from the wrong account, can result in duplicates.
  • Add-Ons or Extensions: Certain Thunderbird add-ons or extensions may interfere with email handling, causing duplicates. Hence, you can try to disable or update add-ons to see if the issue persists.
  • SMTP Server Settings: Incorrect SMTP (outgoing mail) server settings can lead to duplicate email transmission. Ensure your server settings match your email provider’s recommendations.
  • Send Later or Outbox Issues: If you use Thunderbird’s “Send Later” feature or have emails stuck in the Outbox. Then, Thunderbird emails might be sent multiple times if there are connectivity or configuration problems.
  • Imported Duplicates: Sometimes users import MBOX files to Thunderbird using Import/ Export add-ons. But MBOX files may have duplicate clutter and after completing the import process, your Thunderbird may be affected with duplicates.

Recommended: 2 Best Methods to Import PST to Thunderbird

How to Stop Duplicate Emails in Thunderbird?

Above we have discussed various reasons that cause Thunderbird to send emails twice. Hence, there are several solutions available to stop Thunderbird from sending duplicate emails. Use a solution depending on your problem, as mentioned below:

#1 Disable Place a Copy in Sent Folder

  1. Start your Thunderbird email client.
  2. Choose Tools >> Account Settings.
  3. After that, Select Copies & Folders.
  4. Uncheck Place a copy in Sent folder.
  5. Restart Thunderbird and check for problems.

#2 Check Server Settings

  1. Run Thunderbird on your computer.
  2. Select Tools >> Account Settings.
  3. Choose the Server Settings option to continue.
  4. Ensure you have used the correct server settings i.e., Server Type, Server Name, Users Name, Port Number, and Security Settings.

#3 Reconfigure Thunderbird Account Profile

  1. Go to Thunderbird’s profile storage location and create a Thunderbird backup.
  2. Choose Thunderbird Account Settings >> Account Actions.
  3. Select the Remove Account button to delete the configured profile.
  4. Again, choose Thunderbird Account Settings >> Account Actions.
  5. Thereafter, select the Add Mail Account option.
  6. Enter your full name, email address, and password.
  7. Click the Continue button to proceed.
  8. Configuration found in Mozilla ISP database, click Done.
  9. Later you can import backed-up data if required.

#4 Delete Thunderbird POPSTATE.DAT File

Thunderbird creates a popstate.dat file when you configure your email account using POP settings. Its primary function is to retain the status of messages that Thunderbird has fetched from the POP server and retained there. Sometimes popstate.dat file gets corrupted for several reasons. Then You will need to re-create the popstate.dat file to resolve Thunderbird sending duplicate email-related issues. Just follow these steps to delete the popstate.dat file:

  1. Close the Thunderbird client and ensure the hidden files view is enabled.
  2. Navigate to the Thunderbird profile storage location and open the Mail folder.
  3. Now explore the Local Folders and delete the popstate.dat file.
  4. Start Thunderbird client for recreating the popstate.dat file automatically.

Note That: If your computer is affected by viruses then please scan your PC to detect and fix malware problems. Thereafter, you can disable the antivirus program and check problem is fixed or not.

Recommended: Detailed Guide to Compress Thunderbird Email Files

Use Software If Thunderbird Sends Two Emails

BitRecover Thunderbird Duplicate Remover is an excellent software to fix Thunderbird replica emails that are currently available in mailboxes. Hence, first, you need to check Thunderbird settings manually and then use this mentioned software for available emails. The tool comes with a free demo version that analyses the first 25 emails from Thunderbird folders.

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How to Resolve Thunderbird Sending Duplicate Emails?

  1. Launch the software and use the automated option to add Thunderbird profile data.
    add thunderbird profile data
  2. Select the required Thunderbird mailboxes and click Next.
    Select Thunderbird folders
  3. Use a mode to fix Thunderbird clutter within and across folders.
    Select a mode
  4. Enable advance filters to remove duplicate emails by date, email address, and subject.
    Use advance filters
  5. The tool automatically chooses the default destination path to store the resultant data.
    How to stop duplicate emails in Thunderbird
  6. Click the Extract button to start deleting available replica emails across the selected folders.
    Thunderbird sending duplicate emails
In Conclusion

Above we have discussed complete detailed information to stop duplicate emails in Thunderbird. You can follow the mentioned instructions to resolve the Thunderbird sending duplicate emails problem. If you have any other doubts, then contact our support team to get further details.

Read Also: Top 2 Ways to Migrate Thunderbird Mail to Office 365

Frequently Asked Questions

Que 1: How do I stop duplicate emails in Thunderbird?

Ans: You need to check Thunderbird’s account settings and follow the above-mentioned steps depending on your problem. Thereafter, you can stop sending and receiving duplicate emails in Thunderbird.

Que 2: Why is Thunderbird sending emails twice?

Ans: Due to multiple reasons Thunderbird may send duplicate emails, some of the causes are mentioned below:

  • Server syncing issues.
  • Email rules and filter.
  • Multiple account configurations.
  • Wrong SMTP server settings.
  • Imported duplicates.

Que 3: How can I ensure, before importing mailboxes into Thunderbird, that there are no duplicate emails?

Ans: Use BitRecover MBOX Duplicate Remover to fix the mailbox clutter. After that import mailbox to Thunderbird using add-ons.