Thunderbird Email Converter  Univik Thunderbird Email Converter

Excellent TrustScore 4.7 | 1,892 reviews

Convert Thunderbird Emails Easily

The most complete Thunderbird Email Converter, supports multiple profiles, Local Folders, Official & Microsoft Store versions. Preserves read/unread status, attachments and folder structure with 100% accuracy.

  • Auto-detects all Thunderbird profiles, Official & Microsoft Store versions
  • Converts Local Folders alongside account mailboxes
  • Preserves read/unread status, attachments and complete metadata
  • Supports bulk conversion of multiple profiles in one click

*Free trial converts first 10 items per folder. Upgrade for unlimited conversion.

Univik Software Box

CIO Choice Award

Virus Total Safe

Download with Confidence: Certified Clean by 70+ Antivirus Engines

Multiple Profiles
Local Folders
Read/Unread Status
Microsoft Store
100% Integrity

Preserves All Items  Preserves All Email Data

Complete Support  Complete Support

Works With Every Thunderbird Setup

Unlike other tools, Univik Thunderbird Email Converter supports ALL Thunderbird installations, profiles and folder types.

Official Thunderbird
Official Thunderbird

Downloaded from Mozilla website

AppData\Roaming\Thunderbird

✓ Fully Supported
Microsoft Store
Microsoft Store Version

Installed via Windows Store

AppData\Local\Packages\...

✓ Fully Supported
Local Folders
Local Folders

Non-account email storage

All local folders included

✓ Fully Supported
Multiple Profiles
Multiple Profiles

Work, Personal, Archive profiles

Auto-detects all profiles

✓ Fully Supported
Read/Unread Status
Read/Unread Status

Email status preserved

Identify read vs unread emails

✓ Fully Preserved
💡
Why does this matter?

Most Thunderbird converters only work with official installations and ignore Microsoft Store versions, Local Folders or multiple profiles. With Univik, you get complete coverage, no matter how Thunderbird was installed or configured on your system.

Why You Need  Why You Need This

Why Convert Thunderbird Emails?

Thunderbird stores emails in MBOX format, which isn't compatible with Outlook, archiving systems or many business tools. Here's why users need a reliable Thunderbird email converter.

Format Compatibility

Incompatible Format

Thunderbird's MBOX files don't work with Outlook (PST), Windows Mail or most enterprise email systems. Manual methods are complex and error-prone.

✓ Convert to universal formats instantly

Backup & Archive

Backup & Archiving

Need to create backups in standard formats? Export Thunderbird emails to PST, EML or PDF for long-term archiving and compliance requirements.

✓ Secure archival formats supported

Email Client Switch

Switching Email Clients

Moving from Thunderbird to Outlook or another email client? The converter ensures all your emails, folders and attachments transfer perfectly.

✓ Seamless email client migration

Data Integrity

Risk of Data Loss

Manual conversion methods often lose attachments, break folder structures or corrupt metadata. One wrong step and years of emails could be damaged.

✓ 100% data integrity guaranteed

Large Mailboxes

Large Mailboxes

Years of emails mean huge mailbox files. Free online tools crash or timeout. You need software that handles gigabytes of Thunderbird data reliably.

✓ Handles large mailboxes smoothly

Legal & Forensic

Legal & Forensic Needs

Legal proceedings or investigations require emails in specific formats with preserved timestamps, headers and read/unread status for evidence integrity.

✓ Forensic-grade conversion

Data Preservation  Complete Preservation

Everything Preserved, Guaranteed

Every email property, attribute and status is maintained during conversion. Here's exactly what gets preserved.

Email Content Email Content
HTML & Plain Text
Read/Unread Status Read/Unread Status
Exactly preserved
Attachments Attachments
All file types
Flagged/Starred Flagged/Starred
Important markers
Folder Structure Folder Structure
Complete hierarchy
Email Priority Email Priority
High/Normal/Low
From/To/CC/BCC From/To/CC/BCC
All recipients
Inline Images Inline Images
Embedded graphics
Subject Line Subject Line
Complete text
Email Signatures Email Signatures
Formatting intact
Date & Time Date & Time
Original timestamps
Hyperlinks Hyperlinks
Clickable links
Email Headers Email Headers
Full technical data
HTML Formatting HTML Formatting
Colors, fonts, tables
Local Folders Local Folders
All custom folders
Custom Folder Names Custom Folder Names
As-is naming

Multiple Profiles  Multiple Profiles

Convert All Your Thunderbird Profiles

Power users often maintain separate Thunderbird profiles for Work, Personal and Archive. Our converter detects and converts them all.

Profiles Detected Automatically

📧 Default Profile

Official Thunderbird

Selected

C:\Users\...\Roaming\Thunderbird\Profiles\abc123.default

Accounts: 2 | Folders: 47 | Emails: 12,456

📧 Work Profile

Microsoft Store Version

Selected

C:\Users\...\Local\Packages\Mozilla.Thunderbird\...

Accounts: 1 | Folders: 23 | Emails: 5,891

📁 Local Folders

Non-account storage

Selected

Folders: 8 | Emails: 3,245

Total: 3 profiles | 78 folders | 21,592 emails ready for conversion

Why Multiple Profile Support Matters
1

Work vs Personal Separation

Many users maintain separate profiles to keep work and personal emails isolated. Convert both independently or together.

2

Archive Profiles

Old email archives stored in separate profiles? The converter finds and includes them automatically.

3

Different Installation Types

Have Official Thunderbird AND Microsoft Store version? Both are detected and can be converted simultaneously.

4

Selective Conversion

Choose specific profiles to convert or convert all at once. Full control over what gets processed.

Local Folders  Local Folders

Full Support for Thunderbird Local Folders

Local Folders are where many users store important emails that aren't tied to any email account. Our converter handles them completely.

What Are Thunderbird Local Folders?

In Thunderbird, Local Folders is a special storage area that exists independently of your email accounts. Users commonly use Local Folders to:

  • Archive important emails from multiple accounts in one place
  • Store emails that need to be kept even if the account is deleted
  • Organize project-related emails across different clients
  • Create a local backup of critical correspondence
  • Keep emails offline when accounts are removed

Important: Many converters skip Local Folders entirely. Univik includes them by default, no emails left behind.

📁 Local Folders Conversion Preview

📁 Local Folders

├── 📂 Projects

    ├── Client A (234 emails)

    ├── Client B (189 emails)

    └── Internal (456 emails)

├── 📂 Archive 2023

    └── (1,891 emails)

├── 📂 Important

    └── (312 emails)

└── 📂 Legal Documents

    └── (163 emails)

All Local Folders subfolders and their complete hierarchy are preserved in the converted output.

Contacts & Calendars  Beyond Emails

Convert Thunderbird Contacts & Calendars

The Thunderbird Email Converter doesn't stop at emails, it also exports your contacts and calendar data to universal formats.

Contacts

Thunderbird Contacts Export

Export your entire Thunderbird Address Book with all contact details preserved.


Export Formats:

vCard (.vcf) CSV Excel

Preserved Fields:

  • First & Last Name
  • Email Addresses
  • Phone Numbers
  • Company Name
  • Job Title
  • Home Address
  • Work Address
  • Notes & Custom Fields
Calendars

Thunderbird Calendar Export

Migrate all your Thunderbird calendar events, reminders and appointments.


Export Formats:

ICS (iCalendar) CSV

Preserved Data:

  • Event Title
  • Date & Time
  • Duration
  • Location
  • Description
  • Reminders
  • Recurring Events
  • Attendees
Dual Conversion Mode: The software provides separate options to convert Emails and Contacts & Calendars independently. Export only what you need or convert everything together.

Filter Options  Smart Filtering

Advanced Filter Options

Don't convert everything, use powerful filters to export only the emails you need. Save time and get precisely what you're looking for.

Date Range
Date Range Filter

Export emails between specific dates. Perfect for archiving emails from a particular time period, like "all emails from Q4 2024".

From Filter
From (Sender) Filter

Convert only emails from specific senders. Enter an email address or domain to filter emails from particular contacts or companies.

To Filter
To (Recipient) Filter

Export emails sent to specific recipients. Useful for extracting all correspondence with a particular client or team member.

Subject Filter
Subject Filter

Search and convert emails containing specific keywords in the subject line. Find project-related emails or specific topics instantly.

Exclude Folders
Exclude Folders

Skip specific folders during conversion. Exclude Spam, Trash or any folders you don't need in your converted output.

Has Attachment
Attachment Options

Convert emails with/without attachments or extract attachments separately. Control exactly what's included in your output.

📌 Example: Extract Client Project Emails

Filter Settings:

  • Date Range: Jan 1, 2024 – Dec 31, 2024
  • From: *@clientcompany.com
  • Subject contains: "Project Alpha"
  • Exclude: Spam, Trash folders

Result:

✓ Found 234 matching emails
✓ Converted to PST with attachments
✓ Folder structure preserved
✓ Completed in 45 seconds

File Types  Complete Compatibility

Supported Thunderbird File Types

Thunderbird stores data in various file and folder formats. Our converter handles them all seamlessly.

File/Folder Type Description Supported
MBOX Files
(no extension)
Primary email storage format. Thunderbird stores all emails in a mailbox folder as a single MBOX file with no extension. Example: Inbox, Sent ✓ Full Support
.sbd Folders Subfolder structure containers. When you create subfolders in Thunderbird, it creates .sbd directories to store them. Example: Inbox.sbd contains subfolders of Inbox. ✓ Full Support
.msf Files
(Mail Summary Files)
Index files containing email headers and metadata for faster searching. The converter reads these for accurate email properties. ✓ Full Support
.mozmsgs Folders Created when Thunderbird is configured with Windows Search. Contains copies of email data for system search integration. ✓ Full Support
Maildir Directories
(cur, tmp, new)
Alternative storage format where each email is stored as a separate file. Some Thunderbird configurations use this instead of MBOX. ✓ Full Support
.mbox / .mbx / .mbs Exported mailbox files with explicit extensions. Created when exporting emails using add-ons or third-party tools. ✓ Full Support
EML Files Individual email files exported from Thunderbird. Each .eml file contains one email with headers and attachments. ✓ Full Support
Address Book
(abook.sqlite)
Thunderbird's contact database file containing all address book entries and contact groups. ✓ Full Support
Calendar Data
(local.sqlite)
Thunderbird Lightning calendar database containing events, tasks and reminders. ✓ Full Support
📂 Where Does Thunderbird Store These Files?

Official Thunderbird (Mozilla):

C:\Users\[Username]\AppData\Roaming\Thunderbird\Profiles\[profile]\Mail\

Microsoft Store Thunderbird:

C:\Users\[Username]\AppData\Local\Packages\Mozilla.Thunderbird_...\LocalCache\Roaming\Thunderbird\Profiles\

Note: You don't need to locate these files manually, the converter auto-detects all Thunderbird profiles and file locations.

Pricing  Pricing Plans

Choose Your License

Flexible pricing options for individuals, professionals and enterprises. All plans include free updates and technical support.

For Individuals

Personal License

$49 /one-time

  • Single PC activation
  • All output formats
  • Unlimited email conversion
  • Multiple profiles support
  • Local Folders included
  • Free lifetime updates
  • Cloud migration
Buy Personal
MOST POPULAR

For Professionals

Business License

$99 /one-time

  • 3 PC activations
  • All output formats
  • Unlimited email conversion
  • Multiple profiles support
  • Local Folders included
  • Free lifetime updates
  • Cloud migration (Gmail, O365)
  • Priority support
Buy Business

For Organizations

Enterprise License

$199 /one-time

  • Unlimited PC activations
  • All output formats
  • Unlimited email conversion
  • Multiple profiles support
  • Local Folders included
  • Free lifetime updates
  • Cloud migration (Gmail, O365)
  • Dedicated account manager
Buy Enterprise
Money Back Guarantee

30-Day Money-Back Guarantee

Not satisfied? Get a full refund within 30 days. No questions asked. Your purchase is 100% risk-free.

Secure Payment Methods

Visa Mastercard American Express PayPal Stripe

🔒 All transactions are secured with 256-bit SSL encryption

Output Formats  15+ Output Formats

Export Thunderbird to Any Format

The most versatile Thunderbird converter with support for file formats, email clients and cloud services.

Email Formats Email Formats
  • PST Outlook Data File
  • EML Standard Email
  • MSG Outlook Message
  • MBOX Unix Mailbox
  • EMLX Apple Mail
Document Formats Documents
  • PDF Portable Document
  • HTML Web Page
  • RTF Rich Text
  • TXT Plain Text
  • CSV Spreadsheet
Cloud Services Cloud Services
  • Gmail Google Mail
  • O365 Office 365
  • IMAP Any IMAP Server
  • Yahoo Yahoo Mail
  • Zoho Zoho Mail
Contact Formats Contacts/Calendar
  • vCard Contact File
  • CSV Excel/Sheets
  • ICS Calendar File
  • Excel Spreadsheet
  • JSON Data Export

Features  Key Features

Thunderbird Email Converter Features

Professional-grade features designed for accurate, fast and reliable Thunderbird email conversion.

Auto-Detect Profile

Auto-Detect All Profiles

The converter automatically locates ALL your Thunderbird profiles, Official, Microsoft Store and portable versions. No need to manually find MBOX files or profile folders.

Preview Before Convert

Preview Emails Before Conversion

Read and verify your Thunderbird emails before converting. Multiple preview modes show email content, headers, attachments and raw message data for complete confidence.

Folder Structure

Preserves Folder Structure

Your Thunderbird folder hierarchy, Inbox, Sent, Drafts, Local Folders and all custom folders, is perfectly maintained in the converted output. No reorganizing needed.

Read/Unread Status

Read/Unread Status Preserved

Every email's read or unread status is maintained during conversion. After conversion, you can instantly identify which emails were read and which were unread, exactly as in Thunderbird.

Attachments

100% Attachment Preservation

Every attachment, documents, images, PDFs, archives, is preserved and correctly linked to its parent email. Extract attachments separately if needed.

Local Folders

Local Folders Conversion

Thunderbird Local Folders are fully supported. All emails stored outside of account folders are detected and converted with their complete folder hierarchy intact.

Search & Filter

Advanced Search & Filter

Find specific emails before conversion using keyword search, date range filters or sender/recipient filters. Convert only what you need, exactly how you need it.

Bulk Conversion

Bulk Multi-Profile Conversion

Convert multiple Thunderbird profiles in a single operation. Select specific profiles or convert everything at once, ideal for complete migrations and enterprise deployments.

How It Works  How It Works

Convert Thunderbird Emails in 3 Simple Steps

No technical knowledge required. The Thunderbird Email Converter is designed for beginners and professionals alike.

1

Auto-Detect Profiles

All installations found automatically

2

Preview & Select

Verify content, check read/unread

3

Convert & Done

All data preserved 100%

Comparison  Feature Comparison

Univik vs Other Converters

See exactly why Univik Thunderbird Converter is the most complete solution available.

Feature Univik Tool A Tool B Tool C
Multiple Profile Support
Microsoft Store Version
Local Folders Conversion
Read/Unread Status
Auto Profile Detection
Bulk Multi-Profile Conversion
Preview Before Convert
Attachment Preservation
Folder Structure Maintained
Multiple Output Formats 10+ 3 4 5

= Full support  |  = Partial/Limited  |  = Not supported

Integrity Report  Conversion Integrity

See Your Conversion Results

The converter provides a detailed report after every conversion, showing exactly what was processed.

═══════════════════════════════════════════════════════════════
CONVERSION INTEGRITY REPORT
═══════════════════════════════════════════════════════════════

Source: Thunderbird Profiles (3 detected)

📧 Profile: Default (Official Thunderbird)
   ├── Inbox (1,247 emails) ─────────────────► ✓ Converted
   │   ├── Read: 1,102 ──────────────────────► ✓ Status Preserved
   │   └── Unread: 145 ────────────────────► ✓ Status Preserved
   ├── Sent (892 emails) ───────────────────► ✓ Converted
   ├── Drafts (23 emails) ─────────────────► ✓ Converted
   └── Custom Folders (2,156 emails) ──────► ✓ Converted

📧 Profile: Work (Microsoft Store)
   ├── Inbox (3,421 emails) ─────────────────► ✓ Converted
   ├── Sent (1,876 emails) ─────────────────► ✓ Converted
   └── Folders (594 emails) ────────────────► ✓ Converted

📁 Local Folders
   ├── Projects (879 emails) ────────────────► ✓ Converted
   ├── Archive 2023 (1,891 emails) ─────────► ✓ Converted
   └── Important (475 emails) ──────────────► ✓ Converted

📎 Attachments
   └── Total: 4,521 files ──────────────────► ✓ All Extracted

───────────────────────────────────────────────────────────────
SUMMARY: 13,454 emails | 4,521 attachments | 0 errors | 100% SUCCESS
═══════════════════════════════════════════════════════════════

Use Cases  Use Cases

Who Uses Thunderbird Converter?

Real scenarios where our Thunderbird Email Converter delivers the perfect solution.

Personal User

Personal User

Multiple profiles for Work and Personal emails. Needs to convert everything while keeping them organized separately. Auto profile detection saves hours of manual work.

✓ Multiple Profiles ✓ Auto-Detect

Business Migration

Business Migration

Company moving from Thunderbird to Outlook/Office 365. Local Folders contain years of project data that must be preserved. Microsoft Store version used on some PCs.

✓ Local Folders ✓ MS Store ✓ Bulk

IT Administrator

IT Administrator

Managing Thunderbird deployments across the organization. Some users have Official version, others Microsoft Store. Need unified conversion solution for all.

✓ Both Versions ✓ Enterprise Ready

Forensic Investigator

Forensic Investigator

Email evidence for legal proceedings. Read/unread status is critical evidence. Must preserve all metadata including timestamps and headers for court admissibility.

✓ Read/Unread ✓ Headers ✓ Timestamps

Compliance Archiving

Compliance Archiving

Regulatory requirements (GDPR, HIPAA) mandate email retention. Need to archive Thunderbird emails including Local Folders in compliant formats like PST or PDF.

✓ PDF Export ✓ Complete Data

Email Backup

Email Backup

Creating reliable backups of all Thunderbird data before upgrading, reinstalling or switching computers. All profiles and Local Folders must be included.

✓ All Profiles ✓ Local Folders ✓ Safe

Data Sheet  Data Sheet

Technical Specifications

Product details, system requirements and compatibility information.
100%

Score result: Clean  

Tested using VirusTotal technology. 100% safe to download and use.

  • Virus free
  • Spyware free

Supported Thunderbird Versions

Official Mozilla Thunderbird (all versions), Microsoft Store Thunderbird, Portable Thunderbird. Converts MBOX files and profile folders directly.

Univik Software Box
Name: Univik Thunderbird Email Converter
Version: 25.12
Size: 48 MB
Delivery: Free via Email
Free Version:

Free Download
100% Secure

Latest Release

Version 25.12 Features

  • Microsoft Store Thunderbird support
  • Multiple profile auto-detection
  • Read/unread status preservation
  • Enhanced Local Folders conversion

Trial Limitations

Trial Limitations
Trial Limitations:
Free trial converts the first 10 items from each Thunderbird folder. Upgrade to the full version for unlimited conversion of all profiles and Local Folders.

System Requirements

Hard Disk Space: 150 MB free space required (plus space for converted output)
RAM: 4 GB minimum (8 GB recommended for large mailboxes)
Processor: Intel® Core™ i3 or equivalent (i5/i7 recommended)

Platforms

Platforms
Supported Platforms:
  • Windows: 11, 10, 8.1, 8, 7
  • Windows Server: 2022, 2019, 2016, 2012

Pre-Requisites

Pre-Requisites
Pre-Requisites:
  • Standalone software, no additional frameworks required
  • Thunderbird installation NOT required (works with MBOX files directly)
  • Microsoft Outlook NOT required for PST export
  • Works with Official Thunderbird, Microsoft Store and Portable versions

Help Desk  Help Desk

Frequently Asked Questions

Common questions about using the Thunderbird Email Converter.

Simple 3-step process:

  1. Download and launch the Thunderbird Email Converter
  2. The tool auto-detects ALL your Thunderbird profiles, Official, Microsoft Store and Local Folders
  3. Select profiles/folders to convert, choose PST as output format and click Convert

All emails, attachments, folder structure, read/unread status and metadata are preserved in the resulting PST file.

Yes, fully supported. The Thunderbird Email Converter works with both:

  • Official Mozilla Thunderbird, downloaded from thunderbird.net (stored in AppData\Roaming)
  • Microsoft Store Thunderbird, installed via Windows Store (stored in AppData\Local\Packages)

The tool automatically detects the correct profile location for each installation type and loads all mailboxes seamlessly. Most other converters only support the Official version.

Yes. The converter detects and displays ALL Thunderbird profiles on your system:

  • Default profile, Work profile, Personal profile, all detected automatically
  • Select specific profiles or convert all profiles simultaneously
  • Each profile's folder structure is maintained in the converted output
  • Supports both Official and Microsoft Store profiles together

This is especially useful for users who maintain separate profiles for work and personal emails.

Yes, 100%. Thunderbird Local Folders are fully supported and included by default:

  • All emails stored in Local Folders are detected and converted
  • Complete subfolder hierarchy is preserved (Projects, Archive, etc.)
  • Local Folders are shown separately from account folders for easy identification
  • Many other converters skip Local Folders entirely, Univik includes them automatically

Local Folders often contain the most important archived emails that users have manually organized over years.

Yes. The Thunderbird Email Converter preserves the read/unread status of every email:

  • Read emails remain marked as read in the converted output
  • Unread emails remain marked as unread
  • This is critical for forensic investigations and compliance archiving
  • Most competing tools do NOT preserve this status

After conversion, you can easily identify which emails were read and which were unread, exactly as they were in Thunderbird.

Yes, 100%. Every attachment is preserved during conversion:

  • Documents (PDF, Word, Excel, etc.)
  • Images (JPG, PNG, GIF, etc.)
  • Archives (ZIP, RAR)
  • Any other file type

Attachments remain correctly linked to their parent emails. You can also extract all attachments separately if needed.

Both are the same Thunderbird application, but installed differently:

Aspect Official Thunderbird Microsoft Store Version
Download Source thunderbird.net Microsoft Store
Profile Location AppData\Roaming\Thunderbird AppData\Local\Packages\Mozilla...
Updates Manual or auto via Thunderbird Auto via Microsoft Store
Univik Support ✓ Full Support ✓ Full Support

Our converter supports BOTH versions and can even convert them simultaneously if you have both installed.

Absolutely safe. The converter operates in read-only mode:

  • Your original Thunderbird MBOX files are never modified
  • The tool creates new converted files at your specified destination
  • Source files remain exactly as they were before conversion
  • All profiles and Local Folders are untouched

This is a data-safe conversion process with zero risk to your original emails.

The converter supports multiple output formats:

  • Email formats: PST, EML, MSG, MBOX, EMLX
  • Document formats: PDF, HTML, RTF, Text
  • Cloud services: Gmail, Office 365, IMAP servers

Choose the format that matches your destination email client or archiving requirements.

The free trial allows you to:

  • Detect and load all Thunderbird profiles (Official, Microsoft Store, Local Folders)
  • Preview all your emails with full content and attachments
  • Test all conversion features and output formats
  • Convert the first 10 items from each folder

Upgrade to the full version for unlimited conversion of all emails across all profiles and Local Folders.

Still have questions? Contact our support team

Ready to Convert Your Thunderbird Emails?

Download the free trial and convert your first emails in minutes. Supports all profiles, Local Folders and Microsoft Store version.

 Customer Reviews

Trusted by Professionals

See what users say about the Univik Thunderbird Email Converter and its unique features.

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