Thunderbird Address Book abook.sqlite abook.mab Overview

  

Leena Taylor Paul   
Updated: May 12, 2026 • Convert • 6 Min Read

What Are abook.mab and abook.sqlite Files?

Mozilla Thunderbird saves contacts in a dedicated file inside the user profile. The format depends on the Thunderbird version installed on the machine.

Older releases (up to version 60) used the MORK text format. Therefore, the contact file was named abook.mab. MORK is a Mozilla-specific format that is slow to parse and hard to read outside Thunderbird.

Newer releases (78 and later) switched to SQLite. As a result, contacts now live in abook.sqlite. SQLite is a standard database format that any SQL-capable tool can read.

When Thunderbird writes to abook.sqlite, it also creates two temporary files for crash-safe writes:

• abook.sqlite-shm: shared memory file used by SQLite WAL mode.
• abook.sqlite-wal: write-ahead log file used during active writes.

These two files are normal. Do not delete them while Thunderbird is running.

Where Thunderbird Stores the Address Book

The address book sits inside the Thunderbird profile folder. The path varies by operating system.

Windows

C:\Users\<username>\AppData\Roaming\Thunderbird\Profiles\<random>.default\

macOS

~/Library/Thunderbird/Profiles/<random>.default/

Linux

~/.thunderbird/<random>.default/

Each profile folder holds one or more address book files. Personal contacts go into abook.sqlite. Collected addresses go into history.sqlite on newer versions or history.mab on older ones.

How to Back Up the Address Book

Manual backup is straightforward. First, close Thunderbird so no files are locked. Then, copy the contact files to a safe location.

1. Quit Thunderbird completely.
2. Open the Thunderbird profile folder using the paths above.
3. Copy abook.sqlite, abook.sqlite-shm, and abook.sqlite-wal to a backup destination.
4. For older Thunderbird installs, copy abook.mab and history.mab instead.
5. Store the copies on an external drive or cloud folder.

For a complete backup, copy the whole profile folder. This captures contacts, mail folders, settings, and signatures.

How to Migrate Contacts Between Thunderbird Installs

Moving contacts to a new machine takes three steps. First, copy the address book files from the old profile. Next, place them in the new profile folder. Finally, restart Thunderbird to load the imported data.

1. Find the new Thunderbird profile path on the destination machine.
2. Quit Thunderbird on both old and new computers.
3. Copy abook.sqlite (or abook.mab) into the new profile folder.
4. Launch Thunderbird. The address book opens with all the original contacts.

How to Read abook.sqlite Outside Thunderbird

Since abook.sqlite is a standard database, you can open it with any SQLite browser. DB Browser for SQLite is a free option that works on Windows, macOS, and Linux.

1. Install DB Browser for SQLite.
2. Open the abook.sqlite file from your Thunderbird profile.
3. Browse tables such as cards, lists, and list_cards.
4. Run SQL queries or export tables to CSV for analysis.

For older MORK files (abook.mab), use a converter such as mork.pl or migrate the file into a newer Thunderbird version first.

How to Convert Thunderbird Address Book to vCard or CSV

If you plan to move contacts to Outlook, Apple Mail, or a webmail account, convert them first.

1. Open Thunderbird and go to Tools > Address Book.
2. Select the address book to export from the left pane.
3. Choose Tools > Export from the menu.
4. Pick vCard (.vcf) for contact-app imports or Comma Separated (.csv) for spreadsheets.
5. Save the file to a known location.

vCard works for Apple Contacts, iCloud, and most modern address-book apps. CSV works for Outlook, Gmail Contacts, and Google Workspace.

FAQ

What is the difference between abook.mab and abook.sqlite?

abook.mab uses the old MORK text format. abook.sqlite uses a standard SQLite database. Thunderbird 78 and newer use SQLite. Older versions use MORK.

Can I open abook.sqlite in Excel?

Not directly. Excel does not read SQLite. However, you can use DB Browser for SQLite to export the contact table to CSV, then open the CSV in Excel.

How do I extract email addresses from a Thunderbird address book?

Export the address book to CSV or vCard from Thunderbird itself. For deeper extraction, see how to extract email addresses from Thunderbird.

Where does Thunderbird save collected addresses?

Collected addresses go into history.sqlite on Thunderbird 78 and newer, or history.mab on older versions. Both files sit in the same profile folder as abook.sqlite.

Do I need to back up abook.sqlite-shm and abook.sqlite-wal?

Back them up only if Thunderbird was open during the copy. The safer approach is to close Thunderbird first and copy only abook.sqlite.

Can I move Thunderbird contacts to Outlook?

Yes. Export the address book to CSV from Thunderbird, then import the CSV in Outlook via File > Open & Export > Import/Export. You can also convert Thunderbird to Microsoft 365 for a full migration.

In Summary

The Thunderbird address book lives in abook.sqlite on modern installs and abook.mab on legacy ones. Close Thunderbird before copying these files, and use SQLite tools to read them outside the app. For migrations, export to vCard or CSV first, then import into the target client.