How to Speed Up Thunderbird Email Client to Make It Faster?

Rollins Duke   
Published: October 5th, 2023 • 7 Min Read

Do you want to get rid of Thunderbird’s very slow problems and speed up Thunderbird email client’s performance? If your response is yes, then continue to read this article. This article explains the multiple tips and tricks to improve Thunderbird performance.

The Mozilla Foundation created and introduced Thunderbird as an open-source email program, which quickly grew in popularity due to its free access and superior features. These days, Thunderbird is widely used by small businesses, working professionals, and home users alike.

Users configure multiple IMAP and POP email accounts on Thunderbird for sending and receiving emails. But after several years of use, Thunderbird works very slowly due to various reasons, and then users want to speed up Mozilla Thunderbird program.

Recommended: 3 Detailed Ways to Migrate Thunderbird to Office 365

Why Is Thunderbird So Slow?

There are several possible factors contributing to the slowdown of Thunderbird. Here are some of the most common causes.

  • A significant quantity of emails may be available in recipients’ Thunderbird mailboxes.
  • Thunderbird’s individual Mailboxes are approaching their 4 GB size limit.
  • If you are using an outdated version of Thunderbird and your operating system.
  • Certain antivirus programs can impede the speed at which Thunderbird operates, causing it to load slowly.
  • Thunderbird MSF (Mail Summary Files) have been damaged and corrupted.
  • If you have deleted a considerable number of Thunderbird emails without employing the compact header option.
  • Occasionally, the Thunderbird mailbox files located in the storage directory may become corrupted.
  • If you have installed a variety of add-ons to customize and provide additional features in Thunderbird.
  • There is insufficient memory space in the hard disk partition allocated to store Thunderbird data.
  • If you are utilizing outdated hardware on your computer.

Recommended: Technique to Split Thunderbird Inbox Files

Some Issues Associated with Slow Thunderbird Performance

  • Thunderbird is stuck on sending messages and loading messages.
  • Thunderbird keeps hanging up when performing any operation.
  • Your Thunderbird loads very slowly at the time of starting.
  • Mozilla Thunderbird seems very slow to delete messages.
  • Your Thunderbird may freeze and stop sending and receiving messages.
  • Thunderbird works very slowly while typing an email message.

How to Speed Up Thunderbird Email Clients?

There are several methods available to make Thunderbird faster. Let’s check them one by one to speed up Mozilla Thunderbird performance.

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Read Similar: Top 8 Methods to Speed Up Mac Mail Email Client

[1] Make Thunderbird Faster by Emptying Junk

  • Start the ‘Thunderbird’ email program on your computer.
  • Choose the ‘Spam’ folder and right-click on it.
  • Select the ‘Empty Junk’ option from the drop-down menu.
    empty junk
  • Confirming to delete all messages and folders in the Junk folder.
    delete thunderbird junk emails
  • Press ‘Yes’ to empty Thunderbird junk emails.

[2] Improve Thunderbird Performance by Emptying Trash

  • Launch your ‘Thunderbird’ program on your machine.
  • Select the ‘Empty Trash’ option from Thunderbird.
    empty trash
  • Asking to delete Thunderbird Trash emails.
    delete thunderbird trash emails
  • Press the ‘Yes‘ button to start deleting Thunderbird trash.

[3] Run Thunderbird Troubleshoot Mode

  • Run the ‘Thunderbird‘ application and choose ‘Help‘.
  • Afterward, select the ‘Troubleshoot Mode…’ option.
    thunderbird troubleshoot mode
  • Click the ‘Restart’ button to start Thunderbird in Troubleshoot Mode.
    restart in troubleshoot mode
  • Select ‘Disable all add-ons’ or ‘Reset toolbars and controls’ accordingly.
  • Choose the ‘Continue in Troubleshoot Mode’ option and check performance now.
    continue in troubleshoot mode
  • Later, select the ‘Turn Troubleshoot Mode Off‘ option.
    turn troubleshoot mode off

[4] Compact All Folders to Fix Thunderbird Freezes

  • Start your ‘Thunderbird‘ email program.
  • Select the ‘Compact Folders’ option in the ‘File’ menu.
    compact all thunderbird folders
  • Wait to compress Thunderbird email folders.
  • The compact process is completed successfully.

[5] Update Your Thunderbird Client

  • Launch your ‘Thunderbird‘ and select the ‘Help‘ option.
  • Select the ‘About Thunderbird’ option from the drop-down.
  • Check if your Thunderbird is up to date or not.
  • Choose the ‘Release Notes’ option to get information about releases.
  • Update your Thunderbird email client to the latest version.

[6] Configure Automatic Thunderbird Compacting

  • Start ‘Thunderbird‘ open-source email client.
  • Choose the ‘Account Settings’ option under the ‘Tools’ menu.
    account settings
  • Thereafter, select the ‘Disk Space’ option.
    disk space
  • Set up your Thunderbird for automatic email deletion.

[7] Recreate MSF Files via Thunderbird

  • Make sure your Thunderbird should be closed.
  • Find the Thunderbird profile folder and see the MSF files.
  • Delete MSF files that do not store emails.
  • Start your Thunderbird application.
  • Thunderbird will recreate MSF files automatically.

[8] Uninstall Antivirus to Speed Up Thunderbird

  • Type ‘Control Panel’ in the Windows search bar and open it.
  • Choose the ‘Uninstall a program’ option to continue.
  • Select antivirus software and right-click on it.
  • Hit the ‘Uninstall’ option and press ‘Yes’ for confirmation.
  • Antivirus uninstalled successfully from your machine.
[9] Expert Choice to Make Thunderbird Faster

BitRecover MBOX Compress Software is a well-suitable utility that seems like a perfect solution to speed up Mozilla Thunderbird email application. As we all know, Thunderbird stores its mailboxes to MBOX file extension, so first export MBOX file from Thunderbird then perform this suggested software.

This software offers three strategies to improve Thunderbird performance. If Thunderbird hangs while downloading emails, then choose a relevant technique to resolve the issue.


  1. Remove Attachments: Enable this option to remove Thunderbird attachments from all email messages and boost your Thunderbird performance.
  2. Remove Email Header: This feature allows you to remove unnecessary information from the Thunderbird header. However, your crucial header data will be maintained.
  3. Detach Attachments: Enable this option to extract attachments from Thunderbird mailboxes and store them in a separate folder.
[10] Switch Thunderbird to Different Program

If you’re looking for an efficient way to transfer your data from the Thunderbird email client to another application, the BitRecover Thunderbird Converter Wizard is an ideal solution. It is an excellent tool to help you switch from Thunderbird if you’re no longer satisfied with its services.

This software is the perfect solution for converting Thunderbird emails to Outlook, Appl Mail, Windows Mail, eM Client, HCL Notes, and other popular email applications. With 30+ saving options available, you can easily make the transfer with complete convenience and enjoyment.

select saving option

[11] Fix Duplicates to Speed Up Mozilla Thunderbird

If your Thunderbird is working very slowly and you wish to boost its performance, then download the BitRecover Thunderbird Duplicate Remover Tool. This software offers 2 modes to delete duplicate emails within and across the folders. You can also use several advance filter options for fixing replica emails by date range, subject, sender, and receiver information.

Select a mode

The Final Note

We have explained the top 11 ways to speed up Thunderbird email client, check all the possible methods for resolving your queries. Now anyone can easily improve Thunderbird performance if facing slow performance issues.

Frequently Asked Questions

Q 1: How do I speed up Thunderbird startup issue?

A: If you are experiencing issues with Thunderbird freezing, there are several manual methods you can try to resolve the issue. If these techniques do not prove to be successful, then method 9 should be able to help you out.

Q 2: Why is Thunderbird so slow?

A: There are a few possible reasons why Thunderbird might be running slow. These can include too many stored emails, a large mailbox size, a slow internet connection, many add-ons installed, corrupt profile data, an outdated processor, insufficient RAM, etc.

Q 3: Which manual method is recommended to make Thunderbird faster?

A: Enable automatic email deletion in Thunderbird, and timely backup Thunderbird emails to avoid future errors.

Recommended: Tips to Fix Thunderbird Sending Duplicate Emails