How to Import PST to Thunderbird (With or Without Outlook)

Before You Start: Requirement Checklist

Check these before choosing a method. Getting this wrong is the cause of most failed imports.

• Find your PST file: Before you begin, ensure you have a backup copy of the original PST.
• Verify your Outlook installation: If you intend to use Thunderbird’s Outlook Import Tool, you need to have Outlook installed on the same computer.
• Update your Thunderbird: Use the current supported release, not screenshots or instructions from previous releases. Verify
• Available Storage: Make sure there is enough free disk space to store the imported or converted mailbox data.
• Close any unnecessary apps: This can reduce conflicts when both Thunderbird and Outlook are accessing the mail data.
• Identify important directories: Count the approximate number of messages in Inbox, Sent, Archive and important custom folders prior to migration.
• Do not modify the original PST: Do not delete or replace it until you have checked the imported messages and attachments.

Method 1: Import PST with Thunderbird’s Import tool (Outlook installed)

Thunderbird has an inbuilt option to import from Outlook. But in this approach, first you need to move PST file into Outlook. After that, you can import emails from Outlook to Thunderbird.

Requirements: Outlook Classic installed, same bit version as Thunderbird, Outlook set as default mail client and Outlook closed during import.

How to check your bit versions:

• Outlook Classic: File -> Office Account -> About Outlook. The version string ends in 32-bit or 64-bit.
• Thunderbird: Menu -> Help -> About Thunderbird.

If they do not match, then Method 1 will fail. Either reinstall one to match or use method 2/3.

Step 1. Attach PST File to Outlook Profile

Thunderbird can only see mail that is loaded in your Outlook profile. So, first open the PST in Outlook.

1. Launch the Outlook Classic application on your system.
2. Go to File >> Open & Export >> Open Outlook Data File.             
3. Now, choose import from another program or file option and click Next.
4. Select Outlook data file (.pst) as a file type & click Next.                     
5. Browse your .pst file and click Next.                                                       
6. Select the required folders to import from and tap the Finish button.

Now, confirm the PST folders appear in the Outlook left-hand folder pane.

Step 2. Set Outlook as the Default Mail Client

1. Open the Control Panel and navigate to Programs.
   
2. Click Default Programs >> Set your default programs.
3. Select Outlook and click Set this program as default, and then press OK.

Step 3. Run the Thunderbird Import Wizard

1. Close Outlook completely and open Thunderbird.
2. Click on the Menu tab and choose the Tools option.                               
3. Here, select the Import option from the list.     
4. A new tab will appear; select Import from Outlook and click Continue. 
5. Choose what you want to import, i.e., mail, address books or settings.
6. Now, your imported folders are shown in Local Folders.

So, complete now! In this way, you can import & open PST file in Thunderbird.

However, don’t think that this way means Thunderbird will open any PST file directly from your hard disk.

In so many words, Thunderbird’s current documentation says:

• Outlook import needs Outlook to be installed.
• Thunderbird imports Outlook data using Outlook.
• For this import route, a PST file alone is not enough.

Method 2. Move PST Mail Through Gmail or Another IMAP Account

Or you can use an IMAP mailbox as an intermediary for moving messages from a PST into Thunderbird.

The basic workflow is:

PST >> Outlook >> Mailbox IMAP >> Thunderbird

This approach does not let Thunderbird read the PST directly. Instead, Outlook reads the PST then messages are copied or moved to an IMAP mailbox and Thunderbird syncs the mailbox from the server.

Instructions;

1. Open the Outlook application on the PC where you have stored your PST file.
2. Check to see if the PST is available in Outlook. If it is not, then import the PST file as shown in Method 1.
3. Add or open the required Gmail or other IMAP account in Outlook.
4. Then, copy/move the messages you required from the PST folders to mailbox folders of your signed email account.
5. Next, Allow Outlook to synchronise the messages with the mail server.
6. After that, Open Thunderbird application on the same system.
7. Add the same IMAP/email account to Thunderbird.
8. Now, Thunderbird will sync the mailbox of your PST file.
9. After synchronization, check folders and messages.

When should you use this method?

• This can be useful if your mail is already being transferred through an online mailbox and you want Thunderbird to sync it as normal.
• But the large PST archives can take a long time, as the messages need to be uploaded to your mail server first and then downloaded or synchronised by Thunderbird.
• If you have a large archive, check the storage limits of the mailbox before moving thousands of messages.

Method 3. Import PST to Thunderbird Without Outlook

If you have only a PST file and Outlook is not installed, then using an automated tool like Advik PST File Converter is useful. This tool can transfer your PST file into Thunderbird directly. Just add your PST files or folders, select required mailbox, choose Thunderbird saving option and start. It will move all your chosen email folders to Thunderbird local folders without any medium. Thus, it can be considered as a direct way to import PST to Thunderbird without Outlook.

Click on the FREE download button and analyze its working process at no cost.

Basic Steps to Import PST File into Thunderbird

Step 1. Run the tool and read the instructions to carry out this import process.

Step 2. Next, click on Select Files or Folders to add .pst file.

Step 3. Choose the required mailbox folders and click Next.

Step 4. Select Thunderbird as a saving option. (Make sure Thunderbird is installed)

Step 5. Lastly, click the Next button and analyse the import process.

Now, the process has started.

Wait for a while and let the software complete the process. Once complete, you will be notified through a log report consisting of live details of the complete email transfer process.

Now, check the imported folders and messages in local folders of your Thunderbird app.

This is the complete step-by-step process for importing PST emails into Thunderbird.

Watch How to Import PST to Thunderbird Without Outlook

Check Your Emails and Attachments Came Across

Just because Thunderbird shows the imported folders correctly. don’t think that the migration is done.

Check the result before you delete or archive your original PST file.

1. Compare the number of folders: Check important folders like Inbox, Sent Mail, Items Removed, Archive, Drafts, Custom Folders, etc. Compare the number of messages as an approximation to the original Outlook mailbox.

2. Open old and new messages: Choose a few messages from different dates. Check: Sender, Recipient, Subject, Date, Message Body Format, etc.

3. Testing Attachments: Open a few messages that have attachments. Try different attachment types if possible, like PDF, DOCX, XLSX .JPEG/PNG, ZIP and any attachment file types. Ensure the attachment opens and has the expected filename and size.

4. Verify folder hierarchy: If your PST contained nested folders, verify that the corresponding folders were imported or recreated correctly.

5. Look for known emails: Look for a few emails with: Subject name, date, from, unique keywords. This can show missing messages that might not be apparent when browsing the folders.