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How to Fix Thunderbird not Downloading Emails Safely?

By Admin

Updated: April 20, 2026 ~ 7 Minutes Reading

Table of Contents

The “Thunderbird Not Downloading Emails” issue for IMAP or POP accounts restricts a user from accessing them offline or locally. Sometimes, users only see practical content, but Thunderbird fails to download all message content from the server.

Here are the official reasons why Thunderbird may fail to download all email messages with complete content and verified fixes for Thunderbird to reach its optimal potential.

What Does the Thunderbird Stopped Downloading Email Issue Mean?

Most users rely on Mozilla Thunderbird as an email client to access email due to its ability to download emails in offline mode, which offers backup, easy distraction-free work, and access even when traveling.

Mozilla Thunderbird downloads emails from the mail server to your local system. If emails are available in webmail but do not appear locally in Thunderbird, the issue is referred to as “Thunderbird not downloading emails.”

Common Causes of Thunderbird Not Downloading Messages

  • Local sync has been disabled in Thunderbird.
  • Computer or partition storage is full.
  • System permissions are restricted for Thunderbird
  • Corrupted MSF, aka index files.
  • Incorrect IMAP/POP Server or authentication settings.
  • You cannot download new emails in Thunderbird in offline mode.

How to Solve Thunderbird Not Downloading Emails Error Manually?

If Thunderbird is not downloading new messages, then follow these manual steps to fix the issue:

Fix 1: Enable Thunderbird Local Sync

Ensure that the Thunderbird synchronisation settings are set up correctly. If not enabled or if restrictions are set up, Thunderbird cannot download emails.

  1. Open Thunderbird.
  2. Click on Menu (three lines on top right).
  3. Choose Account Settings.
  4. Open the Synchronisation & Storage tab.
  5. Ensure the given box – “Keep messages in all folders for this account on this computer” is checked.
  6. Uncheck the “Don’t download messages larger than” box in case you’re using Thunderbird is downloading some but not all messages.

Learn: How to Download Thunderbird emails to PDF?

Fix 2: Force Download Messages in Thunderbird

If Thunderbird is not downloading all email messages automatically. Follow the steps given below to force download:

  1. Click on File >> Offline.
  2. Choose the Download & Sync Option.
  3. Click on the Select button and choose the mailboxes you want Thunderbird to download.
  4. Finally, press Ok to confirm.

Fix 3: Turn Off Offline Mode

You cannot download new email messages in Thunderbird in Offline Mode.

  1. Go to the Activity bar on the Thunderbird.
  2. Click on the Connection Icon (with red cross) to get out of Offline mode and download messages for the server.

Note: You also need a stable Internet connection to download new messages locally in Thunderbird. If the Thunderbird download message count is stuck

Fix 4: Free Up Computer/ Partition Storage

Thunderbird stores its emails locally in the profile folder on your computer. If the local storage is full, Thunderbird cannot download email messages for local viewing.
In order to free up space, you can:

  • Compact folders in Thunderbird
  • Change Thunderbird profile folder to another drive
  • Delete unnecessary folders to make space for downloading email messages in Thunderbird.
  • You can also archive Thunderbird email to Gmail, Yahoo, or other cloud accounts to free up local storage.

Fix 5: Provide Required Local Permission

Thunderbird fails to download emails locally for offline viewing if local permissions are not provided by the system. Here is how to revoke local restrictions from the Thunderbird application to download messages in Thunderbird.

  1. Open Mozilla Thunderbird.
  2. Click on Menu >> Troubleshooting Info.
  3. Open Profile Folder.
  4. Right-click on the Default Release Folder >> Properties.
  5. Open the Security tab.
  6. Edit the permissions and set all to Allow.
  7. Click on Apply changes and press Ok.

Once the required permissions are given, “Thunderbird not Downloading Emails” issues will be resolved.

Fix 6: Verify Email Server Settings

If Thunderbird cannot connect to the server, Thunderbird stops receiving new emails and it will not be able to download messages as well.

  1. Open Thunderbird and click on the Menu.
  2. Tap on Account Settings and hit Server Settings.
  3. Check the Incoming Mail Server, Port Number, and Authentication Method.
  4. Verify that you have entered the correct credentials based on your Email Account.

Once configured, Thunderbird correctly starts downloading new email messages locally to profile formats in MBOX format automatically.

Fix 7: Repair Corrupted MSF Files

MSF files store email header and location information. A corrupted MSF may wrongly imply that Thunderbird emails are already downloaded. Thus, you must rebuild Thunderbird indexes to fix the issue.

  1. Right-Click >> Properties.
  2. Click on the Repair Folder.
  3. Press Ok.

Fix Thunderbird Not Downloading Emails for POP3 Accounts

Enable Store on Server:
Users with a POP3 account (where emails are only downloaded locally and not stored on the server) can fix Thunderbird not downloading messages
issue as it prevents emails from being removed after the first download:

  1. Go to Account >> Server Settings.
  2. Enable the Leave messages on server option.

Delete popstate.dat:

  1. Close the Thunderbird Application.
  2. Open Thunderbird Profile folder.
  3. Search for popstate.dat.
  4. Deleted the folder.
  5. Restart Thunderbird.
Additional Troubleshooting Steps to Fix Thunderbird Not Downloading Emails
Force Thunderbird to Download All Messages: Pro Tool

If Thunderbird stopped downloading email automatically, use a dedicated Thunderbird Backup Tool to download Thunderbird emails to PST, EML, MBOX, HTML, MSG, and 28+ popular export options for local viewing while maintaining complete data integrity, that too in a 100% offline way.

Steps to Fix Thunderbird not Downloading all Messages
  1. First, install and open the recommended software on your system.load to fix thunderbird not downloading emails
  2. Click on convert emails and select “Configure Thunderbird profile” as you want to convert.add data to fix thunderbird not downloading emails
  3. Choose “Thunderbird mailbox folders” as you want to export.check to fix thunderbird not downloading emails
  4. Select “Export options” in the list of 28+ select saving options.Browse Saving options
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Why Using an External Tool is a Better Solution?
  • It allows you to convert Thunderbird emails to EML, PDF, PST, MBOX, and many more popular extensions.
  • This software is specially designed with a simple, intuitive interface to be easily used by any professional or individual user.
  • You can easily extract phone numbers, email addresses, and attachments from Thunderbird.
  • Offers filter options such as sender blank address, receiver blank address, root folder, exclude folder, subject, from, to, and many more.
  • You can migrate Thunderbird emails to Microsoft 365, Gmail, Yahoo, Zimbra, Apple Mail, and all IMAP-supported email services.
Preventive Measures to Avoid Thunderbird Not Downloading Messages Issue
  • Keeping Thunderbird updated ensures you have the latest security patches, bug fixes, and compatibility improvements.
  • Regularly backup of Thunderbird profile can protect your emails, contacts, and setting form data loss due to corruption or accidental deletion.
  • Use an up-to-date antivirus program that does not interfere with basic application functioning.
  • Track the disk space and profile folder usage, which also helps fix the Thunderbird is so slow issue.
  • Frequently repair MSF files to avoid corruption, which further stops Thunderbird from saving emails locally.
FAQs: Thunderbird Not Downloading Emails

Q1: How many emails can I download locally in Thunderbird?
There is no such restriction; you can download Thunderbird emails locally. However, local download is restricted by disk-scape and server protocols.

Q2: Why can’t I open emails offline in Thunderbird?
This is because Thunderbird fails to download emails offline. You need to force download emails to fix the issue.

Q3: Why does Thunderbird Android not download emails?
This is because the Thunderbird Android app supports only IMAP-based sync and does not create a profile folder for local storage.

Observational Verdict

Thunderbird is a reliable email client, but when it fails to download messages, and even sometimes Thunderbird fails to send emails, it can affect productivity. Thunderbird continuously checks for new emails and downloads messages bit by bit. However, when users configured Thunderbird not to download emails, it led to a critical situation. To fix this error and prevent such issues in the future, applying the right solutions and preventive measures is essential.