Written by Jennifer Walsh. Reviewed for technical accuracy by Shubham Dixit, Independent Expert in Email Forensics and Data File Conversion. Updated 18 September 2026.
Shubham is an independent external reviewer and not an employee of PCDOTS.
Quick answer. Thunderbird keeps everything in one profile folder, the mail, address book, filters and settings. The easy way is Tools then Export, which saves the profile to a ZIP you restore with Import, for profiles up to 2 GB. For a bigger profile, close Thunderbird and copy the profile folder to an external drive. The ImportExportTools NG add-on backs up chosen mail and can run on a schedule.
On this page
- Where does Thunderbird keep your data?
- How do you back up Thunderbird with the built-in Export?
- How do you back up a large profile by copying the folder?
- How do you back up with the ImportExportTools NG add-on?
- How do you restore a Thunderbird backup?
- When does a backup tool help?
- Which method should you use?
- Frequently asked questions
Where does Thunderbird keep your data?
Thunderbird keeps everything in one place, your profile folder. That single folder holds the mail, the address book, the filters, the settings and even your saved passwords. So a backup is really just saving that folder.
That’s good news, because it means you don’t need paid software to back up. Thunderbird has a built-in Export that zips the profile, you can copy the folder yourself or an add-on can save chosen mail. All three are free.
One point on IMAP accounts. That mail also lives on the server, and the profile holds the local copy, so it’s smart to keep mail you care about in Local Folders, which the backup always captures in full.
The routes below run easiest first. Start with the built-in Export, and drop to the folder copy only for a big profile.
Everything sits in the profile folder, so saving it backs up all of Thunderbird.
“People go looking for backup software, and Thunderbird already has what they need. Everything lives in the profile folder, so I tell them to use Tools then Export for a quick ZIP, which Import puts back later. The only catch is the 2 GB ceiling on that ZIP, so for a big mailbox I close Thunderbird and copy the folder to a drive instead, no limit and nothing to install. If someone wants it running on a schedule, the ImportExportTools NG add-on does automatic backups. A converter only earns its place when you want the backup in PST or PDF to open without Thunderbird.” Shubham Dixit, Email Data reviewer (draft, pending approval)
How do you back up Thunderbird with the built-in Export?
You back up Thunderbird with the built-in Export, which saves the entire profile to a ZIP file. It’s the official way, and the same tool’s Import restores it later, even on another computer.
Here are the four steps.
- Open the Thunderbird menu, then Tools, then Export.
- Click the Export button in the dialog that appears.
- Choose a location and a dated name, like Thunderbird_backup_2026.zip.
- Click Save. Copy the ZIP to an external drive or the cloud for safety.
For a quick backup I use Tools then Export, since it captures the accounts, mail, address books and settings in one ZIP. This ZIP has a 2 GB limit, so if your profile is bigger, use the folder copy below instead. Mozilla sets this out in its profile export guide.
Tools then Export saves a ZIP of the profile, and Import restores it.
How do you back up a large profile by copying the folder?
You back up a large profile by copying the profile folder yourself, which skips the 2 GB ZIP limit. Close Thunderbird first so the files aren’t in use, then copy the folder to a safe spot.
Here are the four steps.
- In Thunderbird, open the menu, Help, then Troubleshooting Information, then next to Profile Folder click Open Folder.
- Go up one level, then fully close Thunderbird.
- Copy the profile folder, the one ending in .default-release.
- Paste it onto an external drive, another partition or a cloud folder.
The profile sits at %APPDATA%\Thunderbird\Profiles on Windows, ~/Library/Thunderbird/Profiles on a Mac, and ~/.thunderbird on Linux. To restore, close Thunderbird and copy the folder back into place.
How do you back up with the ImportExportTools NG add-on?
You back up chosen mail with the free ImportExportTools NG add-on, the plugin most people mean by a Thunderbird backup add-on. It exports folders to MBOX or EML, and it can run backups on a schedule.
Add it from Menu, Add-ons and Themes. Then right-click a folder, choose ImportExportTools NG, then Export folder, then select EML for a backup you can import again. For a hands-off setup, the add-on’s Automatic Backup saves your mail on a timer to a folder you choose.
How do you restore a Thunderbird backup?
You restore a Thunderbird backup with the same route you saved it. The method matches the backup you made, so choose the one that fits.
For an Export ZIP, open Tools, then Import, then select the ZIP. For a copied profile folder, close Thunderbird and paste the folder back into its location. For an ImportExportTools NG backup, use the add-on’s Import to bring the MBOX or EML files back in. Any route puts your mail, contacts and settings back where they were.
This is also how you move to a new computer. Take the ZIP or the profile folder to the new machine, install Thunderbird, then Import the ZIP or drop the folder in. It’s worth a quick test too, restore into a spare profile once, so you know the backup opens cleanly before you need it.
When does a backup tool help?
A backup tool helps when you want the backup in a portable format you can open without Thunderbird, like MBOX, PST for Outlook, or PDF for an archive. It reads the Thunderbird mail and saves it in the format you choose.
PCDOTS Thunderbird Converter loads your Thunderbird accounts and saves the mail to MBOX, PST, PDF or EML on Windows, keeping the folders and attachments. It runs without Thunderbird open, and filters by date or sender. The free trial saves a sample first. Follow these four steps.
- Install and run PCDOTS Thunderbird Converter, then open the menu.
- Open Desktop Email Clients, then Thunderbird, then let it load the mail.
- Preview the mailbox, then select the folders you want.
- Open Export, select a format, then a destination, then save.
The tool route, a portable Thunderbird backup in MBOX, PST or PDF.
Here are the first steps with the screens.
Step 1. Install and run PCDOTS Thunderbird Converter.
Step 2. Open Thunderbird Accounts and load the mail.
Step 3. Preview the mailbox and select the folders.
Related reading, our guides to export Gmail to Thunderbird and import EML files to Thunderbird. To read a saved file, the free Thunderbird viewer opens it.
Match the backup to your case, a normal profile, a big one, a schedule or a portable copy.
Which method should you use?
Use the built-in Export for a normal profile, a folder copy for a big one and a tool for a portable format.
| Method | Best for | Good to know |
|---|---|---|
| Tools, Export ZIP | A normal profile | Free, restore with Import, 2 GB limit |
| Copy the profile folder | A large profile | Free, no size limit, close first |
| ImportExportTools NG | Chosen mail, on a schedule | Free add-on, MBOX or EML |
| Thunderbird Converter | A portable format | Windows, MBOX, PST or PDF |
Key takeaways
- Thunderbird keeps mail, contacts, filters and settings in one profile folder, so a backup saves that folder.
- Tools then Export makes a ZIP of the profile, and Import restores it, up to 2 GB.
- For a big profile, close Thunderbird and copy the profile folder to an external drive.
- The ImportExportTools NG add-on backs up chosen mail and can run on a schedule.
Frequently asked questions
How do I back up Thunderbird for free?
Open Tools, then Export, to save your entire profile to a ZIP. For a profile over 2 GB, close Thunderbird and copy the profile folder to an external drive instead.
What does the backup include?
The profile holds it all, the mail, address book, filters, settings and saved passwords. Saving the profile backs up every part of Thunderbird, not just the emails.
How do I restore a Thunderbird backup?
For an Export ZIP, use Tools then Import. For a copied folder, close Thunderbird and paste it back. For an add-on backup, use ImportExportTools NG Import.
Where is the Thunderbird profile folder?
At %APPDATA%\Thunderbird\Profiles on Windows, ~/Library/Thunderbird/Profiles on a Mac, and ~/.thunderbird on Linux. Help then Troubleshooting Information opens it too.
Can Thunderbird back up automatically?
Yes, with the ImportExportTools NG add-on’s Automatic Backup, which saves your mail on a timer. You can also script a folder copy with Task Scheduler or cron.
How do I back up Thunderbird on a Mac?
The same way. Use Tools then Export, or close Thunderbird and copy the profile folder from ~/Library/Thunderbird/Profiles to a drive.
So how are you backing up Thunderbird?
Backing up Thunderbird is free, because everything lives in one profile folder. Tools then Export zips it in a click and Import brings it back, for a profile up to 2 GB. For a bigger one, close Thunderbird and copy the folder to a drive. An add-on handles chosen mail on a schedule, and a tool makes a portable MBOX, PST or PDF copy. So how are you backing up Thunderbird, a quick Export, or a full folder copy?
