Error

Why Does Thunderbird Always Expand Threads? Top Fixes

By Admin

Updated: February 10, 2026 ~ 6 Minutes Reading

Table of Contents

As users of Mozilla Thunderbird we know that Thunderbird always expand Threads. Sometimes users need to find a particular message in the conversation but are unable to find it. Moving forward we will talk about how to disable Thunderbird threads while keeping all the data intact.

Thunderbird expand all threads by default and that cannot be changed until we delete the emails due to its large thread or set the default to “unthreaded” in the Config Editor and then apply that view to all folders via the column options menu. As our Thunderbird mailbox contains important emails, we cannot just delete them.

There is always a solution and we are going to find it anyway with this blog to disable Thunderbird threads .

What Does Thunderbird Always Expand Threads Mean?

When threading is enabled, Thunderbird group related emails under one conversation. Normally, these threads stay collapsed until you click on the arrow next to it. If Thunderbird always expands threads, it means every conversation opens automatically whenever you open a mail folder, switch between folders or just restart your Thunderbird email client.

This results in a long cluttered message list, especially if you receive multiple replies in the same conversation.

Common Reasons Thunderbird Keeps Expanding Threads

  • Expand All Threads Enabled: Thunderbird allows users to control how threads appear. As If users choose to Expand All Threads from the option, every thread will be automatically opened by default.
  • Folder-Specific View: Thunderbird saves view preference per folder. Even if threads are collapsed in one folder, another one may still force expand threads.
  • Order Conflicts: Threads work best when you sort your emails by “Dates”. Sorting emails by sender, subject, or any other column can easily cause Thunderbird to expand threads unexpectedly.
  • Corrupted Folder Index (MSF File): A damaged folder index file can cause strange display behavior and that includes always open threads too.
  • Saved View or Quick Filter: Custom views or quick filter settings can be the reason sometimes that your default thread behavior and force expansion.

How to Fix Thunderbird Always Expanding Threads Error?

There are multiple ways to disable Thunderbird threads, but users need to be careful while working on them to get accurate results. As Thunderbird expands all threads by default, below are listed methods that can help you to easily close them whenever you want with ease.

Method 1: Collapse Threads Manually

  1. First of all, open Thunderbird on your system.
  2. Now, go to the affected mail folder.
  3. Click on the View option from the above menu.
  4. After that, select Threads.
  5. Click on Collapse All Threads.

This way all the open threads will collapse with in the conversations. However, you need to regularly do this in future as well to fix it.

Method 2: Disable Permanently

  1. Open the folder where threads expand automatically.
  2. Now, click on View >> Threads.
  3. Make sure Expand All Threads is unchecked.
  4. See Threaded is enabled only if you want conversations grouped.

You need to repeat these steps for other folders, as Thunderbird applies this setting individually.

Method 3: Set Proper Sorting Order

  1. First Open your Mail folder.
  2. After that, click on the Date column header.
  3. Ensure sorting is set to the Descending order as newest on top.

This process works correctly only when emails are stored by date. Other options result in thread expansion forcefully.

Method 4: Apply the View Settings to All Folders

  1. First right-click on the folder with correct thread behaviour.
  2. After that, choose Properties.
  3. Now, go to the General Information tab.
  4. Click on Use default view setting option.
  5. Lastly, click on the OK button to finish.

This method will help you to normalize folder display behaviour across all folders and disable Thunderbird threads.

Method 5: Repair Email Folders

  1. Right-click on the affected email folder.
  2. Now select the Properties option.
  3. After that, click on the Repair Folder.
  4. Wait for Thunderbird to rebuild the inbox folder.

This method does not delete emails but refreshes the folders displayed.

Method 6: Check Global Configuration

  1. Click on Settings >> General.
  2. Now, scroll down and click on Config Editor.
  3. Now, search for mailnews.thread_pane_expand_all
  4. Once done, restart Thunderbird after making all the changes.

Still Stuck with Expanded Threads in Thunderbird?

As your Thunderbird may have some important and crucial emails and conversations. No matter if they are personal or professional, they are meant to be preserved in a proper way. If Thunderbird continues to expand email threads even after making these changes and adjustments, it’s high time to backup Thunderbird Profile data at the safest place where it is easy to access and read your emails and conversations without any expanding threads and display issues.

Best Way to Fix Thunderbird Always Expand Threads

Thunderbird Backup Tool is a one-stop solution that helps users to save all Thunderbird data into a compatible and easy to use format. This way all your conversations will be safe and secured and you can access them whenever you want. You just need to download this solution and start the process to disable Thunderbird threads.

Quick Steps to Use this Solution

  1. First of all, download and install the solution on your system and click on Next button.
    install to fix thunderbird always expand threads
  2. Now, choose an option to load your Thunderbird data into the panel and click on Next button again.
    load data to fix thunderbird always expand threads
  3. Now, check and preview all your uploaded data carefully. You can even select only those files and emails that are important to you.
    preview data
  4. Now, choose a file format of your choice to save your data into your storage carefully.
    choose format
  5. At last, choose a destination path and click on Next button to proceed.

What Else does this Solution Offer?

  • It saves all Thunderbird emails in a clean, readable format where all your conversations do not auto-expand, which helps users to avoid thread display issues permanently.
  • Securely backups all your mailbox data along with emails, folders, and attachments without making any changes and altering your Original Thunderbird setup.
  • It helps you maintain the originality and hierarchy so that the users can easily locate conversations without dealing with expanded or cluttered threads.
  • Allows users to choose specific folders or emails, making it easy for the users to preserve all the important conversations and crucial messages.
  • It transforms Thunderbird data into a widely supported format for smooth access outside Thunderbird, free from view or storing conflicts.
  • It works without deleting, modifying or damaging the existing Thunderbird data that ensures complete data backup without losing integrity.

Preventing the Issue in the Future

  • Make sure to keep your folders sorted by Date filter.
  • Avoid changing threads settings as per needs frequently.
  • Repair your email folders if it displays any issue.
  • Use the same view settings across folders.

The Final Words

We have discussed multiple ways to fix Thunderbird Always Expand Threads issue in this above blog. As Thunderbird expanding threads automatically is usually caused by view settings, storing conflicts, or folder specific preferences of the user. By disabling it, you can keep your email folders clean and clutter-free.

You can try all these above mentioned fixes or just simply backup Thunderbird profile folder entirely to access all these important emails safely. You can contact our Technical Support Team in case of any query or need of assistance.