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Thunderbird Release Notes

Thunderbird is a full-featured email, RSS and newsgroup client that makes emailing safer, faster and easier than ever before. More information about Thunderbird is available.

These Release Notes cover what's new, download and installation instructions, known issues and end user support / feedback for the Thunderbird Please read these notes and the bug filing instructions before reporting any bugs to Bugzilla.

We want to hear your feedback about Thunderbird. Please join us in the Mozilla Thunderbird Support forum, hosted by MozillaZine.

What's New in Thunderbird

Thunderbird provides stability and security enhancements that are part of our ongoing program to provide a safer email experience for our users. We recommend that all Thunderbird users upgrade to this latest version.

Here's what's new in Thunderbird

  • Universal Binary Support for Mac OS X which provides native support for Macintosh with Intel Core processors. Thunderbird supports the enhancements to performance introduced by the new MacIntel chipsets.
  • Improvements to product stability.
  • Several security fixes.

The Rumbling Edge has a more detailed list of notable bug fixes.

Release Date: June 1, 2006

Downloading and Installing

System Requirements

Before installing, make sure your computer meets the system requirements. Starting with 1.5, Mac OS X users must have Mac OS X 10.2 or greater.

Downloading Thunderbird

The Mozilla Foundation provides Thunderbird for Windows, Linux, and Mac OS X.

Windows: Installer

Linux: GTK2 + XFT (no installer)

Mac OS X: Compressed Disk Image

For builds for other systems and languages not provided by, see the Contributed Builds section at the end of this document.

Installing Thunderbird

Once you have downloaded a Thunderbird installer or compressed archive, follow these instructions to install:


Double click the Thunderbird Setup installer to start the install.


Once you have downloaded the Thunderbird file, double click the Thunderbird Disk Image to open it in Finder, and then drag the Thunderbird application onto your hard disk. Drag the icon to your Dock if you want it to appear there.

Other Platforms

Extract the compressed archive and run thunderbird

Uninstalling Thunderbird

To uninstall Thunderbird, follow these instructions:


From the Start menu, choose Control Panel. When the Control Panel appears, double click Add/Remove Programs. Find "Mozilla Thunderbird (" in the list and click Remove to uninstall.


Drag the Thunderbird application to the Trash.


Remove the thunderbird folder.

These instructions leave your profile in place in case you install Thunderbird again in the future. If you wish to remove your profile folder, remove the location described below in the "Profile Folder" section. Note that by doing this you are destroying all of your email, address book data, settings and other information and should you decide to use Thunderbird again you will be starting with a clean profile.

Other Information

Profile Folder

Thunderbird stores your user data in one of the following locations:

Windows 2000, XP Documents and Settings\<UserName>\Application Data\Thunderbird
Windows NT WINNT\Profiles\<UserName>\Application Data\Thunderbird
Windows 98, ME Windows\Application Data\Thunderbird
MacOS X ~/Library/Thunderbird
Linux and Unix systems ~/.thunderbird

Known Issues

This list covers some of the known problems with Thunderbird Please read this before reporting any new bugs, and watch it regularly (we'll update it as new bugs are found in the release).

Extensions and Themes

You may run into issues with our new Extension Compatibility and Update mechanism. There are simple workarounds for each of the three problems we're aware of.

  • If after you run the Thunderbird installer, the extension compatibility and update wizard does not appear, go to the Extension Manager and manually check for updates.
  • If the Extension Compatibility and Update wizard appears but does not complete, first try to focus some other window and return focus to the wizard. If that does not correct the problem, hit Cancel and go to the Extension Manager and manually check for updates.
  • If the Extension Compatibility and Update wizard downloads and installs extension updates but those updates are not applied, open the Extension Manager and manually check for updates.
  • On Intel-based Macintosh computers, PowerPC-only binary extensions do not work unless users upgrade to an Intel-native or Universal version or turn on Rosetta. To turn on Rosetta, click on the Thunderbird icon, click "Get Info" and then check the "Run Under Rosetta" box.

Extensions installed under Thunderbird 1.0 may be incompatible and/or require updates to work with Thunderbird Please report any issues to the maintainer of the extension. When you install Thunderbird all of your Extensions and Themes may be disabled until Thunderbird determines that either a) they are compatible with the release or b) there are newer versions available that are compatible. This is because Thunderbird changes from release to release and as such the ways in which some extensions integrate changes, meaning there can be problems when running an older extension with a newer version of Thunderbird. If you find that your favorite Extension or Theme has not been updated to be compatible with this release of Thunderbird, write the author and encourage them to update it.

All Systems

  • Some firewall software may silently block Thunderbird from running. Most firewalls will ask you whether to allow a program to connect to the Internet. It's important that you always grant Thunderbirde access. If you deny access, you must go into the firewall's configuration program and re-allow access. Even when disabled, some firewalls deny access. Here is some more information on configuring your firewall.
  • If Thunderbird is installed on a multi-user system in a location which is not writable by users, Thunderbird must be run once by a privileged user. If this is not desirable, an empty file must be created in the following directory: <install-directory>/extensions/
  • The default dictionary is English-only. To add a non-English dictionary, read the installation instructions.
  • When switching between using a Global Inbox and using an Inbox for a POP3 account, be sure to make copies of the messages into another folder.
  • Software Update will not work if Thunderbird is installed to a location that you do not have write access to, since Software Update needs to replace or create files in this location.


  • When installing as a restricted access user on a shared machine into a location that you can write to, there may still be negative side effects (default email/other keys not being set correctly). The email client should still function however. When installing as a restricted access user do not attempt to install over an installation in a restricted-access/shared location as this may destroy that installation.
  • Windows users can sync their address book with a Palm device by installing the Palm Sync extension for Thunderbird. Save the file locally and install it from the extensions dialog in Thunderbird. The extension will not show up in the list of extensions. You will have to restart Thunderbird after installing the extension before it will take effect.


  • If you are running Thunderbird 1.5 or Thunderbird on Macintosh computers with Intel Core processors under Rosetta, you will get upgraded to a PowerPC-only, Thunderbird product via the automated update system. You will need to download the Thunderbird Universal Binary build from to take advantage of the native support for Intel-based Macintosh computers.
  • There is no Talkback on Intel-based Macs when running natively or under Rosetta. The Apple Crash report program should launch in the event of application crashes.
  • The new mail notification system sound is not working on Intel-based Macs when running natively. This will be fixed in the next update.

Linux and Unix systems

  • GNOME integration does not work properly with Fedora Core 3. Users of Fedora Core 3 will need to download and install linc-1.0.3-3.1.i386.rpm. After installing the RPM, perform the following command in the directory you installed Thunderbird into (you will need write permission):

    touch .autoreg

    The next time you start Thunderbird, GNOME integration should be functional.


Frequently Asked Questions

  1. What can I do to help?

    We need all the exposure we can get. Make it your mission to convert as many of your friends, family members and coworkers as possible. If you're a student, get it distributed at your college. Submit a story to Slashdot and other news sites about the release. Make some noise on your blog. Mass distribution via the Internet is possible -- look at Kazaa.

  2. Why haven't you responded to the mail I sent you?

    Use the forums. The Thunderbird team reads them regularly. We all get a lot of email and your email may get lost.

  3. Where can I get themes and add-ons (extensions)?

    Extensions and themes can be downloaded from Mozilla Update.

  4. Who is working on Thunderbird?

    Lots of people. See Help->About Mozilla Thunderbird, Credits for a list of some of the people who have contributed to Thunderbird.


The following resources contain useful information about Thunderbird:


Contributed Builds

These are unofficial builds and may be configured differently than the official builds. They may also be optimized and/or tested for specific platforms.

Solaris (contributed by SUN Desktop Beijing Team)

Tarball format (README)

Pkgadd format (README)

Other Systems

Builds for platforms other than the trio officially offered by can be found on the FTP site.

Localized Builds

Many localized builds are now produced and distributed by on behalf of their authors. Visit or view All Systems and Languages to see the set of official builds that we offer.


Previous versions of the Release notes: 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | 1.0 | 1.0.2 | 1.0.5 | 1.0.6 | 1.0.7 | 1.0.8 | 1.5 |