Corbett

Thunderbird Migrator

Corbett Thunderbird Migrator opens Thunderbird mail files on Windows and moves mail to Gmail, Office 365 or an IMAP mailbox. Folders and attachments stay intact. Try free demo first.

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4.6 out of 5 from 683 reviews

Works from your PC. Corbett never sees your Thunderbird mail.

Free demo, scanned clean on VirusTotal and a 30-day money-back window.

Lifetime licence from $299 Demo migrates 10 emails per folder

Migration scope

Thunderbird Migrator for Thunderbird Mail on Windows

Thunderbird Migrator Saves Mail for Any Target

Thunderbird keeps mail in mbox files inside your profile, and years of mail sit there. Thunderbird migrator opens those files on Windows and moves mail to Gmail, Office 365 or IMAP, or saves it as PST, EML, MBOX or PDF.

Kept in output

Email body and headers
Attachments
Sender and receiver
Dates and subjects
Folder tree

Thunderbird input

MBOX files
Local Folders
Profile Mail folders
Single files or full folders

Outputs

Gmail
Office 365
IMAP
PST
EML
MBOX
PDF
HTML
TEXT and CSV
Thunderbird

Not needed

Corbett account
Upload to Corbett
Extra software
Subscription

Where Thunderbird keeps your mail

Mozilla Support article on Thunderbird account directories says Thunderbird keeps the mail of every folder in an mbox file with no file extension, and puts Local Folders in the Mail folder of your profile. Thunderbird Migrator opens those mbox files and moves your mail where you need it.

Thunderbird to another computer

Related pages: Gmail Migration Tool, Yahoo Mail Migration Tool, Thunderbird Backup Tool and IMAP Migration Tool. Other mail files sit on email converter tool page.

Core features

Thunderbird Migrator Features by Screen

Five screens of Corbett Thunderbird migrator, in migration order.

Open menu with Email Data Files submenu listing PST, OLM, MBOX, EML, MSG, OFT, DBX, Google Takeout, MailDir and vCard files

Source files

Open Thunderbird MBOX Files from the Open Menu

Select Open, then Email Data Files, then MBOX Files. Thunderbird stores every folder as an mbox file, so your Thunderbird mail opens in the wizard.

Thunderbird Migrator needs no Thunderbird install on your PC.

Batch loading

Choose Files or Choose Folders

Select Choose Files for one mbox file or a few. Select Choose Folders to load a profile Mail folder in one step.

Loaded mail appears in one tree with a checkbox beside every folder, so one session covers many Thunderbird folders.

Email preview with content, header, properties, hex and raw views

Message preview

Preview Thunderbird Mail Before You Migrate

Click any message and a reading pane opens beside the message tabs. Content shows the body, Message Header lists the sender and routing data, and the hex and raw views show the stored mail.

Check a few messages first, so the right folders go to your target.

Export menu with email file, document file, email service and email client formats

Output formats

Select Your Thunderbird Migration Target

The Export menu groups targets. Email Files hold EML, MBOX and PST. Document Files hold PDF, HTML, TEXT and CSV.

Email Services hold Gmail, Office 365 and IMAP, and Email Clients hold Thunderbird. Select a service and your mail lands in that mailbox instead of a file.

Office 365 Export Options with backup folder name, email address and password boxes

Target options

Enter Your Target Details and Save

Export Options asks for a backup folder name, the target email address and its password. Switch on create empty folders, include email headers or append into default folders.

Press Save and live progress shows the job. A button opens your target mailbox when the transfer ends.

Working process

How to Migrate Thunderbird Mail in Four Steps

Four steps take your Thunderbird mail to its target. Try them on a few folders in free demo first.

Open Thunderbird mail

Start Thunderbird migrator, select Open, then Email Data Files and MBOX Files. Choose files or choose folders.

Preview and select folders

Your Thunderbird folders load as one tree. Click any email to preview it, then tick the folders you need.

Choose a target

Select Export, then Gmail, Office 365 or IMAP under Email Services, or choose a file format.

Save to your target

Enter the target address and password, set options and press Save. A button opens your target mailbox when the transfer ends.

Longer walkthroughs sit in Import MBOX to Gmail and Import MBOX to Office 365 mail.

Working process

Thunderbird Migrator Video Walkthrough

Prefer text? Open Thunderbird to another computer for every click with screenshots.

Advanced options

More Thunderbird Migrator Features for Big Jobs

Small options that save hours when you migrate Thunderbird mail in bulk.

Folder hierarchy

Target follows your Thunderbird folder tree

No file size limit

Any Thunderbird size and mail count

Message preview

Content, header, hex and raw message

Quick search

Find mail by keyword before export

Empty folders option

Keep the full tree, even with no mail

Cloud targets

Send mail to Gmail, Office 365 or IMAP

File targets

PST, EML, MBOX and PDF copies

Thunderbird target

Send mail to another Thunderbird

USB and NAS targets

Save output to external drives and network storage

Error logs

Show Error Logs in Export Options

Append option

Append into default folders toggle

Advance Search

Search mail before you export

Output formats

Thunderbird Migrator Output Formats

Thunderbird migrator sends mail to mailboxes or saves it as files. Match your target to where your mail will open.

Gmail, Office 365 and IMAP

Mail lands in the target mailbox

PST

A file Outlook opens

EML

One file for every message

MBOX

One file per folder for Thunderbird and Apple Mail

PDF

Readable pages for filing and records

HTML

Messages that open in any browser

TEXT and CSV

Plain text and sheets of mail details

Thunderbird

Mail goes straight to the client

Free demo

Test Thunderbird Migrator on Real Thunderbird Mail

Install free demo, open your Thunderbird mail and choose a target. Free demo migrates 10 emails per folder, so your output is quick to check.

Download free demo

Try before you buy

Free Demo vs Full Thunderbird Migrator

Free demo of Thunderbird migrator opens, previews and searches your Thunderbird mail. Only migration is capped.

Feature	Free demo	Full version
Open Thunderbird files and preview mail	Yes	Yes
Preview and search	All available	All available
Emails migrated per folder	10	Unlimited
Mailbox size and mail count	Migration stops at 10 per folder	No limit
Price	Free	From $299 one time

Use cases

Who Needs a Thunderbird Migrator?

Anyone who holds mail in Thunderbird and needs it somewhere else.

IT admins

Move staff Thunderbird mail to Office 365 when your team changes platform.

People leaving Thunderbird

Move old Thunderbird mail into Gmail or Outlook.

Legal and compliance teams

Save Thunderbird mail with headers and attachments intact for review and discovery.

Archive keepers

Save Thunderbird mail as PST, PDF or EML files that you store offline.

Owners of an old PC

Open mail from a Thunderbird profile copied off a retired computer.

Selective movers

Choose folders and search mail, then move only what you need.

Why Corbett

Why Choose Corbett Thunderbird Migrator?

No subscription

Lifetime price from $299

Local transfer

Mail moves from your PC to your target

Source stays put

Your Thunderbird files stay where they were

No Thunderbird needed

Open mbox files with no install

No size limit

Any Thunderbird size and mail count

Folders kept

Folders and subfolders stay in order

Smart search

Name, subject, To, From and content

30-day refund

Money-back window after purchase

Before migration

Thunderbird Migrator Scope and Limits

Thunderbird migrator opens Thunderbird mbox files and moves mail to mailboxes or files. Here is what that covers and where it stops.

Capability	Supported	What it means
Thunderbird to mailbox	Yes	Gmail, Office 365 and IMAP sit under Email Services
Thunderbird to files	Yes	PST, EML, MBOX, PDF, HTML, TEXT and CSV
Folder tree	Kept	Your target follows your Thunderbird folders
Local Folders	Yes	Load the Mail folder of your profile
Source Thunderbird files	Stay as they were	Output goes to a mailbox or folder you choose
Licence	Business or Enterprise	Mailbox targets sit outside the Personal licence, which saves files only
Mac and Linux	No	Thunderbird migrator installs on Windows only

Manual route or tool

Thunderbird Migrator vs Drag and Drop

Dragging folders into a new account inside Thunderbird costs nothing. Here is where that stops, and where Thunderbird migrator takes over.

Job	Drag and drop	Thunderbird migrator
Cost	Free	From $299 one time
Targets	Accounts set up in Thunderbird	Gmail, Office 365 and IMAP
PST or PDF copy	Not offered	Saved from the Export menu
Search before export	Search inside Thunderbird only	Advance Search and quick search

Mozilla describes where Thunderbird keeps mail in Mozilla Support article on Thunderbird account directories. Add the new account in Thunderbird and drag folders across.

Global recognition

Thunderbird Migrator Software Users Trust

Users rate Corbett Thunderbird migrator 4.6 out of 5 from 683 reviews, and these software directories list it.

CNET
Download.io
UpdateStar
TopSoftware Advisor
SaaSHub
Uptodown

Specifications

Thunderbird Migrator Specifications

Download details

Download size: 87.4 MB
Demo limit: 10 items per folder
Delivery: After payment, mail arrives with a download link and a licence key.
Licence: Personal: 5 machines. Business: 25 machines. Enterprise: 100 machines. Lifetime validity.

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System

Hard disk: 150 MB of free space
RAM: 4 GB of memory minimum
Processor: 1 GHz Intel Pentium minimum and 2.4 GHz advised
Interface: English
Input: MBOX files and desktop clients

Supported editions

Windows 11 (64 bit), 10, 8 and 7 in 32-bit or 64-bit, plus Windows Server 2016, 2012 R2 and 2008.

Start Thunderbird migrator with administrator rights.

Corbett has built Windows email utilities since 2020. Setup trouble and first-use questions go to our support desk.

User testimonials

Thunderbird Migrator Reviews

Thunderbird migrator shares 683 reviews on software index sites and customer feedback.

4.6 out of 5

Collected across 683 reviews from software indexes and customer feedback. Three reviews below are unedited.

Large IMAP move, patient support

I had a large amount of data to migrate from Thunderbird to IMAP server, and I connected with their support executive Nick. He was patient and helpful in completing the entire process.

Jack H. Pankratz

Install error fixed fast

I initially had an installation error and connected with one of their support executives who helped me resolve it. The best part of the Thunderbird Migrator is that they provide quick assistance at any time of the day.

Dean J. Sliva

Before migration

Prepare Your Thunderbird Mail for Migration

Three short checks keep your Thunderbird migration clean.

Find your profile folder

Mozilla places mail in the Mail and ImapMail folders of your profile. Copy the profile folder to a safe drive before you start.

Get your target login ready

Gmail needs an app password, and Office 365 and IMAP targets need the address and password of the new mailbox.

Leave space for output

PST and PDF output needs free room on the destination disk, and a target mailbox needs free storage.

Setup help sits in Add Gmail to Thunderbird. Mailbox targets need the Business or Enterprise licence on the Corbett buy page.

Best practice

How to Keep Your Thunderbird Migration Safe

A migration only helps if your mail arrives complete. Four habits keep your data safe through it.

Back up first

Copy your Thunderbird profile before you start. Keep 3 copies on 2 types of media with 1 copy off site.

Start with one folder

Migrate one small Thunderbird folder and open a few emails in your target. Catch a wrong setting before a large job.

Check the count

Compare the message count in the folder tree with the mail in your target before you close the job.

Keep originals until checked

Store your Thunderbird profile until counts match. Remove Thunderbird only after you open migrated mail.

Common questions

Thunderbird Migrator FAQs

Thunderbird migrator steps, formats, limits and licence answers.

What is Thunderbird migrator?

Thunderbird migrator opens Thunderbird mail files on Windows and moves your mail to another mailbox or to files. Corbett Thunderbird Migrator sends mail to Gmail, Office 365 and IMAP, or saves PST, EML, MBOX, PDF, HTML, TEXT and CSV.

How do I migrate Thunderbird to Office 365?

Select Open, then Email Data Files and MBOX Files, and load your Thunderbird folders. Select Export, then Office 365 under Email Services, enter the target details and press Save.

How do I migrate Thunderbird to Gmail?

Load your Thunderbird mbox files, select Export, then Gmail under Email Services. Enter your Gmail address and an app password, then press Save.

Which password does Gmail need?

Google Account Help on app passwords says an app password needs 2-Step Verification and has 16 digits. Create one in your Google Account and enter it in the password box.

Where does Thunderbird keep my mail?

Mozilla Support article on Thunderbird account directories says mail sits in the Mail and ImapMail folders of your profile, with Local Folders under Mail, and every folder is an mbox file with no extension.

Do I need Thunderbird installed?

No. Thunderbird migrator opens mbox files on its own, so a profile folder copied from an old PC works.

Are Local Folders migrated?

Yes. Local Folders sit in the Mail folder of your profile, so load that folder and tick Local Folders in the tree.

Does Thunderbird migrator keep my folder tree?

Yes. Your Thunderbird folders load as one tree, and the Create empty folders option keeps folders that hold no mail.

Can I move Thunderbird to a new PC with Outlook?

Yes. Select Export, then PST under Email Files, and open the PST in Outlook. See Export Thunderbird to PST for the steps.

Can I save Thunderbird mail as PST?

Yes. EML, MBOX, PDF, HTML, TEXT and CSV sit in the same Export menu.

Can I send mail to an IMAP server?

Yes. IMAP sits under Email Services in the Export menu. Enter the server details of your target account.

Can I migrate only some Thunderbird folders?

Yes. Tick the folders you need, or search by keyword and move only matching mail.

Can I preview Thunderbird mail first?

Yes. Click any message and message tabs open, including Content, Message Header, Hex View and Raw Message.

Does Thunderbird migrator keep attachments?

Yes. Attachments stay with every message when you move mail to a mailbox or save it as files.

Does Thunderbird migrator have a size limit?

No. Thunderbird migrator sets no size cap. Transfer time depends on your connection, so keep your PC awake until the job ends.

Will Thunderbird migrator change my Thunderbird files?

No. Your files stay where they were, and the copy goes to the target you choose.

Does my Thunderbird mail pass through Corbett?

No. Migration happens from your PC with no upload to Corbett. Corbett never sees your Thunderbird mail.

How many emails can free demo migrate?

Free demo opens your files, shows every folder and gives you every search and preview. Migration stops at 10 emails per folder, enough to test your target before you buy.

Which licence do I need to migrate Thunderbird to a mailbox?

Gmail, Office 365 and IMAP saving options sit in the Business licence at $299 and the Enterprise licence at $499. The Personal licence at $99 saves PST, PDF and other files only.

Which Windows versions work?

Windows 11 (64 bit), 10, 8 and 7, plus Windows Server 2016, 2012 R2 and 2008. There is no macOS or Linux build, so copy a Mac profile to a Windows PC.

Can I load several Thunderbird profiles?

Yes. Load the Mail folder of every profile you copied, and every mbox file joins the same tree. Tick the folders you need and export them together.

Is there a refund?

Yes. Request a refund within 30 days of purchase. See the refund policy for details.

Thunderbird guides

Thunderbird Migrator Guides for Common Jobs

Every page below covers one Thunderbird job and answers questions it raises.

Thunderbird to cloud mail

Thunderbird to Outlook

Into Thunderbird

Other migration pages cover Gmail Migration Tool and Yahoo Mail Migration Tool. Server mailboxes use the IMAP Migration Tool, and every mail source sits on the Email Migration Tool page. Save a copy first with Thunderbird Backup Tool or the Gmail Backup Tool. Other mail files sit on the email converter tool page, broken archives belong with email recovery software and email viewer software opens saved mbox files free.

Get started

Migrate Thunderbird Mail Today

Test Thunderbird migrator on a few folders first. Mailbox targets need the Business licence at $299 or Enterprise at $499, and refunds are open for 30 days.

Download free demo Purchase now

87.4 MB · Windows 11 to 7 and Windows Server 2016 to 2008 · 30 day money back