Thunderbird not deleting messages from server is not a bug but something caused by your account settings. To resolve it, change the delete settings, empty trash, or adjust the IMAP or POP3 retention setting.

For IMAP accounts, deleted messages are moved only to Trash or marked as deleted. For POP3 accounts, a copy of messages is kept online if “Leave messages on server” is ticked.

To check your account type, open Account Settings from the drop down menu list (three horizontal lines on top right corner) and click Server Settings. Once you figure out which server you are working on– IMAP or POP3, you will understand the right fix.

This guide explains all possible types of fixes that you can perform and check if your Thunderbird is not deleting messages.

Table of Contents

Key Takeaways

  • Thunderbird not deleting messages from server is usually a settings fault, not an actual software issue.
  • If  Thunderbird is set offline or any folder is corrupted, it can stop the deletion of messages.
  • Removing the account is the last method you can go for if nothing resolves the problem.
  • Messages saved on the server keep using your storage until you empty your Trash folder.

Why Is Thunderbird Not Deleting Messages From Server?

The possible reasons why Thunderbird is not removing messages from your server are-

  1. IMAP delete case– If your account uses IMAP, its default behavior may only move messages to Trash or mark them as deleted instead of removing them permanently. The messages stay on the server until you delete them.
  2. ‘Leave message on server’ setting– if your server is POP3, the setting in POP3 server allows it to keep a copy of messages on the server for a set number of days. This is the main reason for Thunderbird POP3 not deleting messages from server.
  3. Device’s own delete rules– a device with its own delete rules can restore or keep the deleted messages copies saved.
  4. Gmail rules- It has its own rules and may keep your deleted messages saved in All Mail folder.

What Happens When Messages Stay On Thunderbird Even After Deletion?

When Thunderbird fails to delete messages from server, the messages may not be visible in the inbox but still exists in your online mailbox. This can cause several issues–

  • Deleted emails reappear– these mails appear again on your phone, in webmail, or in another email client.
  • Your mailbox space gets filled– These deleted messages stay on your server and occupies space in the storage, which can fill up your storage quota easily.
  • Device syncing gets disturbed– one device shows a clean inbox while another still shows deleted mails.
  • Reinstalling or syncing can duplicate it– Old messages may download again when you reinstall Thunderbird or add the account to a new device.

How To Fix Thunderbird Not Deleting Messages From Server? 4 Methods To Follow

  1. Change IMAP Server Settings
  2. Fix POP3 server’s ‘Leave message on server’ issue
  3. Fix Gmail Deletion Settings
  4. Check If Thunderbird is offline or has a corrupted folder

If you want to remove deleted messages from the server, you can make changes in your server settings (IMAP or POP3), Gmail settings, or check if your folder is corrupted, or if any another device is bringing back deleted emails.

Let’s check the step-by-step guide–

Change IMAP Server Settings

  1. Thunderbird stores your emails on the server if you are using IMAP. If you delete a message, it either moves it to Trash folder or mark it as deleted. To fix it, change the delete behaviour of the IMAP.
  2. To change Thunderbird server settings, click on the menu (three horizontal lines on top) and select Account Settings. Under Server Settings, look for When I delete a message block. Select one of the following options–
      • Move it to this folder– Sends the message to Trash, where it stays until you delete it.
      • Just mark it as deleted– It hides the message but does not delete it from the server.
      • Remove it immediately– Permanently removes the message from the server.
  3. Select the ‘Remove it immediately’ option and it will delete the message from your server permanently once you delete it.

Note– Always empty your Trash folder and compact your folders to save the storage space and keep your Thunderbird running.

Fix POP3 Server’s ‘Leave message on server’ Issue

With POP3, Thunderbird downloads your mail and deletes the copy of it that is saved on the server. If you face Thunderbird POP3 not deleting messages from the server,

  1. Go to Server Settings in Account Settings and find Leave message on server option under Manage Storage.
    There will be three options available for you–
    • Read mail on one device only: Untick Leave messages on server. Thunderbird will not save any copy on the server.
    • Read mails on more than one device: Keep it selected and choose Until I delete them. Thunderbird will delete those messages from server which you will delete locally.
    • Using ‘For at most X days’: The server keeps messages until the set date range and then deletes them from the server.

Fix Gmail Deletion Settings

  1. Gmail by default removes messages only from the Inbox folder when you delete them over IMAP, keeping the messages still in All Mail folder. To fix this issue–
  2. Open Gmail through web login and go to its Settings and select See all settings. Choose Forwarding and POP/IMAP from the given options.
  3. Under the option for messages to be deleted from the last label or marked as deleted, select Move the messages to the Trash or Immediately delete the message forever.
  4. Save the changes and restart Thunderbird.

Check If Thunderbird Is offline Or Has a Corrupted Folder

  1. Open Thunderbird and press Alt key once. You will see the basic menu bar appeared on the top.
  2. Click on View and from the drop-down menu select Offline. Under this, you will see the Work Offline option. Make sure it is not ticked.
  3. Right-click on your account and click Get Messages option to force the sync.

If the problem still exists–

  1. Right-click the affected folder and select Properties from the options.
  2. Click on Repair Folder and now Thunderbird will re-sync it with the server, which often fixes Thunderbird not deleting messages from server issue.

Remember– Other devices can also cause the problem. Devices using POP3 server with ‘leave messages on server’ can keep copies, and other may have their own delete rules. Always review the settings on every device and make sure they work in sync.

What To Do If The Issue Is Not Resolved?

If still nothing resolves your issue, remove the account and add it again. Before removing it, backup Thunderbird emails you do not wish to lose while re-adding the account. Thunderbird will download a fresh copy of the mailbox and rebuild the settings.

Read more-  You can also export your emails in various formats like PST, EML, PDF, NSF, MSG, HTML, EMLX, and CSV using SysTools Thunderbird Converter.

Conclusion

Thunderbird not deleting messages from the server is usually caused by a settings issue, or when your server keeps a copy of it instead of deleting it. Thunderbird follows what you allow it through settings and a few minutes in review your account settings can fix all such issues. Start with knowing your server and its behaviour with the mailbox, empty Trash and compact folders frequently, and review the connected devices. Once you find the actual cause of the issue, deletion will be possible across all devices and your folders will remain synced and under the storage limit.

FAQs

  1. Can I permanently delete Thunderbird messages from the server?
    Yes. You can enable ‘Remove it immediately’ option from the settings or press Shift + Delete key which allows files to skip the Trash folder and get deleted permanently after a confirmation prompt.
  2. How to get a deleted email back in Thunderbird?
    After deletion if the email is in the Trash folder, you can get it back easily. Email providers have their own number of days limit to keep the file in the Trash and delete it permanently after the limit exceeds.
  3. Do attachments get deleted with the emails in Thunderbird?
    Yes. Attachments are part of the emails and gets deleted when the message is deleted from the server.
  4. Can I restrict Thunderbird from keeping local copies of deleted messages?
    To restrict Thunderbird from keeping local copies of deleted messages, go to Account Settigs (menu bar) and under Synchronization & Storage heading, turn off keeping messages for offline use for your account. Then you can compact the folder to completely remove them from the local file.
  5. Which server option is better for keeping deletions in sync, IMAP or POP3?
    Choose IMAP. It keeps all devices synced with the server, so deleting on one device helps you delete it from everywhere. POP3 is made for one device and keeps a separate copy for each.