How to Move a Thunderbird Profile to Another Drive or Computer Safely

Moving a Thunderbird profile is different from reinstalling Thunderbird. The profile contains your account settings, messages stored locally, address books, passwords, and preferences. If Thunderbird opens a fresh profile after a move, your mail may look missing even though the original data still exists.

The safe approach is to make a separate backup, close Thunderbird completely, copy the profile data, and then point Thunderbird at the copied profile or restore the data into a profile created at the destination. The exact route depends on whether you are moving to another drive on the same computer or to a different computer.

What a profile move does—and what depends on your setup

Before you move anything

1. Confirm the source profile. In Thunderbird, open the menu, choose Help, then Troubleshooting Information. Beside Profile Folder, click Open Folder (the wording can vary slightly by operating system). This opens the folder Thunderbird is currently using.
2. Make a backup. Close Thunderbird, then copy the profile folder to a different location, such as an external drive. Keep this untouched copy until the moved profile is working and your important mail has been checked.
3. Check the Thunderbird versions. For a move to another computer, Mozilla recommends that both installations be up to date or use the same version before transfer. This reduces compatibility problems when the destination opens profile data written by the source.
4. Wait for Thunderbird to exit. Close all Thunderbird windows and give background processes time to stop before copying. Do not copy a profile while the application is writing to it.

Mozilla’s support page lists common profile locations—such as %APPDATA%\Thunderbird\Profiles\ on Windows, ~/Library/Thunderbird/Profiles/ on macOS, and ~/.thunderbird/ on Ubuntu—but custom installs and packages can differ. Use the in-app Profile Folder link instead of assuming one of these paths is yours.

Move a profile to another drive on the same computer

This method creates a profile entry at the new location and then fills it with the copied data. It avoids relying on a folder-name guess or manually editing profile configuration.

1. Open Profile Manager. In Thunderbird, use Help > Troubleshooting Information and open the about:profiles page. You can also close Thunderbird and launch the Profile Manager with thunderbird -P on Linux, or the platform-specific Thunderbird executable followed by -P on Windows or macOS.
2. Create a destination profile. Choose the option to create a profile, give it a descriptive name such as “Mail on D Drive,” and choose a new, empty folder on the target drive when asked where to store it. Mozilla specifically warns against choosing a non-empty folder during profile creation.
3. Finish creation and close Thunderbird. If the new profile opens, quit Thunderbird before copying any files. Note the destination profile folder using Troubleshooting Information or the profile manager.
4. Copy the source profile contents. Open the backed-up source profile and copy everything inside it into the new destination profile folder. Copy the contents, including hidden files and folders, rather than placing the source folder itself inside the destination as an extra nested directory. Allow files with matching names to be replaced in the newly created profile.
5. Start the destination profile. Reopen Thunderbird and select the new profile in Profile Manager if it is not selected automatically. Check that accounts, folders, address books, and settings appear before removing or renaming the old profile.

Keep the original profile where it is until the new one has passed your checks. A profile on a separate internal drive is still only one copy; drive failure can affect both the application and its data if you do not maintain an independent backup.

Move Thunderbird data to another computer

There are two practical options. Use Thunderbird’s export and import tools when the profile fits the export limit and the tools are available in your version. Mozilla’s current Export page says profile backups are ZIP files and the built-in export currently supports files up to 2 GB. If your profile is larger, use a file manager to copy it.

Option A: Export and import the profile

1. On the source computer, use Thunderbird’s Tools > Export command, choose a destination, and save the ZIP archive.
2. Transfer the archive to the new computer using a USB drive or another safe transfer method.
3. Install or update Thunderbird on the destination computer, then use its Import Tool to restore the profile archive.
4. Open the restored profile and verify the accounts and local data before deleting the source copy.

If the Export command is unavailable or the profile exceeds 2 GB, use the manual method below. Do not split or modify Thunderbird’s internal profile files unless you understand the format.

Option B: Copy the Thunderbird data folder

1. Close Thunderbird on both computers.
2. On the source computer, locate the Thunderbird data folder. Mozilla’s cross-computer guide recommends copying the Thunderbird folder that contains the profile configuration and profile data, rather than copying only a random subfolder.
3. Copy the folder to external media or another transfer destination. Do not use a live synchronized profile as the transfer method while Thunderbird is open on either computer.
4. On the destination, install Thunderbird and start it once only if you need it to create its initial data folder; then close it. Rename the destination’s existing Thunderbird data folder as a temporary backup instead of deleting it.
5. Copy the transferred Thunderbird folder into the matching data location for the destination operating system. If the profile was stored in a custom location, use Profile Manager to create a profile that points to that restored location.
6. Start Thunderbird and check that the intended profile is selected. Keep both the source and destination backups until you have verified the move.

When moving between different operating systems, do not paste a Windows path into macOS or Linux. The profile data can be copied, but the destination’s profile manager and filesystem paths must match that computer. If the profile is not detected, use the Profile Manager to create a profile at the restored location or restore the backed-up contents into a newly created profile.

Common assumptions to avoid

“If I reinstall Thunderbird, it will move my profile.”

Verified: Thunderbird program files and profile data are separate. Reinstalling the program normally does not relocate a profile. Action: perform the copy and profile-selection steps yourself, then confirm the Profile Folder points to the intended drive.

“IMAP means I do not need a profile backup.”

Depends: IMAP mail is generally synchronized with a server, but local folders, account settings, address books, passwords, and cached or offline mail still rely on local profile data. What can be downloaded again depends on the provider and account configuration. Action: verify server access and make a profile backup before the move, especially if you use Local Folders or offline mail.

“A cloud-synced profile is a safe way to use Thunderbird on two PCs.”

Verified: Mozilla says simultaneous access to a profile from multiple running Thunderbird instances is unsupported and can lead to corruption or permanent data loss. Cloud storage is not a backup. Action: transfer a closed profile, or use separate profiles and an email account’s normal synchronization features instead of opening the same profile on both computers.

“A profile folder is usable on any Thunderbird version.”

Depends: compatibility may be affected by version differences. Mozilla advises using versions that are up to date or identical for computer-to-computer transfers. Action: update Thunderbird on both computers before migration, and do not open the only copy with an older installation.

Check that the move worked

Open Thunderbird with the destination profile and confirm that the expected accounts, folders, address books, message filters, signatures, and settings appear. Open a few older messages, including messages stored under Local Folders if you use them. Confirm that passwords are present or can be entered again, then send and receive a test message for each account.

In Troubleshooting Information, verify that Profile Folder opens the destination path. If Thunderbird opens a blank account-setup screen, quit without adding accounts; reopen Profile Manager and select the moved profile. If data is missing, stop using that destination profile and restore from the untouched backup before trying another copy.

Keep the original profile and a separate backup for several days. After the new drive or computer is confirmed, you may remove old copies when convenient, but keep a regular backup routine. Moving a profile changes where Thunderbird reads its data; it does not protect that data from disk failure, accidental deletion, or profile corruption.

Official Mozilla references

• Profiles: Where Thunderbird stores your messages and other user data
• Move Thunderbird data to a new computer
• Profile Manager: Create and remove Thunderbird profiles
• Export your Thunderbird Profile

Mozilla support pages checked October 6, 2026. Profile paths and some menu labels can vary by operating system, Thunderbird release channel, and installation method.