MailtoPst
FR
PST Thunderbird

Convert PST to Thunderbird
Online Tool

Migrate Outlook PST emails to Mozilla Thunderbird. Convert PST to MBOX or EML with MailtoPst, then import directly into Thunderbird. Free, cross-platform solution.

Convert now → See how it works
🛡️ GDPR Compliant 🔒 TLS 1.3 Encryption 🇪🇺 Hosted in EU 🇫🇷 Built in France 🗑️ Auto-delete 24h

What is a PST file?

PST (Personal Storage Table) is Microsoft Outlook's primary data file format, storing emails, calendar data, contacts, and tasks in a binary database file. PST files are the standard export format from Outlook and are commonly found when users switch away from Microsoft's email ecosystem.

PST files need to be imported into Thunderbird when:
- Abandoning Microsoft Outlook — switching to the free, open-source Thunderbird client
- Moving from Windows to Linux — Thunderbird is the dominant email client on Linux distributions
- Cost reduction — eliminating Microsoft 365 license fees in favor of free software
- Open-source preference — choosing community-maintained software over proprietary solutions
- Multi-platform needs — Thunderbird runs identically on Windows, macOS, and Linux

Thunderbird cannot open PST files directly. The emails must be converted to MBOX (Thunderbird's native format) or EML before import.

What is a Thunderbird file?

Mozilla Thunderbird is the world's most popular free, open-source email client. Developed by the Mozilla Foundation (creators of Firefox), Thunderbird provides a full-featured desktop email experience on Windows, macOS, and Linux.

Thunderbird strengths for former Outlook users:
- Completely free — no license fees, no subscription, no feature restrictions
- Open-source — transparent development, community-driven improvements
- Cross-platform — identical experience on Windows, Mac, and Linux
- Extension ecosystem — thousands of add-ons for additional functionality
- Privacy-focused — no data collection, no telemetry by default
- Standard protocols — IMAP, POP3, SMTP, CardDAV, CalDAV support
- Active development — Thunderbird 128+ (Supernova) brings a modern redesigned interface

Thunderbird stores emails in MBOX format and supports EML file import, making it straightforward to migrate from Outlook once the PST is converted.

Why convert PST to Thunderbird?

Migrating from Outlook PST to Thunderbird offers compelling benefits:

1. Zero software cost
Thunderbird is completely free — no Microsoft 365 subscription needed. For organizations with many users, this can save thousands of dollars annually.

2. Cross-platform freedom
Unlike Outlook which works best on Windows, Thunderbird provides the same experience on Windows, macOS, and Linux. Your email client follows you regardless of which OS you use.

3. Privacy and data sovereignty
Thunderbird stores all data locally and does not send telemetry to any company. Your emails remain entirely under your control, with no cloud dependency.

4. Linux migration
For users moving to Linux (Ubuntu, Fedora, etc.), Thunderbird is the natural email client choice. Importing PST data ensures continuity of your email history on the new platform.

5. Extension flexibility
Thunderbird's add-on ecosystem offers features like advanced email filtering, encryption (OpenPGP built-in), calendar integration, and more — all free and community-maintained.

PST vs Thunderbird — Key Differences

Feature PST Thunderbird
Cost Microsoft 365 subscription required Completely free (open-source)
Platform Best on Windows Windows, macOS, Linux (identical)
License Proprietary (Microsoft) Open-source (MPL 2.0)
Data storage PST (proprietary binary) MBOX (open standard)
Extensions COM add-ins (limited) Rich add-on ecosystem (free)
Privacy Microsoft telemetry No telemetry by default

3 methods to convert PST to Thunderbird

Method 1: Convert PST to MBOX with MailtoPst, import in Thunderbird

Convert your PST to MBOX format using MailtoPst. In Thunderbird, use the ImportExportTools NG add-on or the built-in import wizard to import the MBOX files. Your emails appear in Thunderbird with the original folder structure.

Pros

  • ✓ MBOX is Thunderbird's native format
  • ✓ Fastest import method
  • ✓ Preserves complete folder structure
  • ✓ No Outlook needed

Cons

  • ✗ May need ImportExportTools NG add-on
  • ✗ Requires internet for conversion
  • ✗ Paid after first MailtoPst conversion

Method 2: Convert PST to EML, drag into Thunderbird

Convert your PST to individual EML files with MailtoPst. Open Thunderbird and simply drag the EML files from your file manager into the desired Thunderbird folders. Thunderbird natively understands EML files.

Pros

  • ✓ Simplest method (drag-and-drop)
  • ✓ No add-ons needed
  • ✓ Selective import possible
  • ✓ Works on all platforms

Cons

  • ✗ Slower for thousands of emails
  • ✗ Manual folder creation needed
  • ✗ Individual files take more disk space
Recommended

Method 3: Thunderbird's built-in Outlook import (Windows only)

On Windows with Outlook installed, Thunderbird can import directly from Outlook during setup. Go to Tools > Import or use the setup wizard to import emails from a configured Outlook profile.

Pros

  • ✓ Direct import, no conversion needed
  • ✓ Built-in Thunderbird feature
  • ✓ Imports contacts and calendar too

Cons

  • ✗ Requires Outlook installed on Windows
  • ✗ Windows only
  • ✗ May not work with all Outlook versions
  • ✗ Cannot import standalone PST files without Outlook
Try MailtoPst →

Step by step

How to convert PST to Thunderbird with MailtoPst

01

Upload your PST file

Drag & drop or click to upload your .pst file. Files up to 51 GB supported with resumable upload.

02

Choose Thunderbird as output

Select Thunderbird from the format dropdown. MailtoPst auto-detects the best conversion settings.

03

Download your Thunderbird file

Conversion takes seconds. Download your .thunderbird file or receive it by email.

Convert your PST to Thunderbird now →

100 MB free credit. No credit card required.

FAQ

Frequently Asked Questions

Can Thunderbird open PST files directly?

No. Thunderbird cannot read PST files natively. You need to convert the PST to MBOX or EML format using MailtoPst, then import the converted files into Thunderbird. On Windows with Outlook installed, Thunderbird can import from Outlook's profile but not from standalone PST files.

Which format is better for Thunderbird import: MBOX or EML?

MBOX is Thunderbird's native storage format, so it is the most efficient choice for large imports. EML is better for selective imports where you want to choose specific emails. For a full mailbox migration, MBOX is recommended.

Will my Outlook folder structure be preserved in Thunderbird?

Yes. MailtoPst preserves the folder hierarchy during conversion. When importing MBOX files, each folder becomes a Thunderbird folder with the same name and hierarchy. Subfolders are preserved as nested folders.

Can I do this migration on Mac or Linux?

Yes. MailtoPst is web-based and works on any OS. Thunderbird is available on Windows, macOS, and Linux. The entire PST-to-Thunderbird migration can be done on any platform without needing Windows or Outlook.

What about Outlook calendar, contacts, and tasks?

MailtoPst focuses on email conversion. For calendar data, you can export from Outlook as ICS files and import them using Thunderbird's built-in calendar. Contacts can be exported as CSV or VCF and imported into Thunderbird's address book.

Related conversions

EML → Thunderbird MBOX → Thunderbird OST → MBOX PST → EML PST → MBOX
See all 30 conversion paths →

Ready to convert your emails?

First conversion free. No credit card required.

Start converting → See pricing