From MozillaZine Knowledge Base

Before upgrading to a newer version of Thunderbird, make sure to read the release notes for any comments about installing or upgrading. Version 1.5, for example, is unusual in that it wants you to install into an empty directory (folder) when upgrading. Normally you can rely upon the Thunderbird setup program to delete the older version's (program, not personal) contents if you're upgrading into the same directory (folder) as the older version.

When you upgrade, the new version of Thunderbird should automatically detect your existing profile(s), containing your mail, address books, and settings, and start up with these intact, just as they were before. Because profiles are by default stored completely separately from the Thunderbird program installation directory, they should not be deleted or otherwise affected when you uninstall an old version of Thunderbird or install a new version. However, to be on the safe side, you should make a temporary backup of your profile(s) before upgrading.

There is more than one way you can upgrade. Some users, for instance, might choose to keep an older version of Thunderbird on their computer even after they install a newer one so that they can fall back on the older version if they wish. Below are upgrade procedures that should work well for general users.

Windows (installer version)

1. Make a temporary backup of your profile folder(s).
2. Decide where you want to install the new version of Thunderbird (normally in a subfolder of "Program Files"). Unless you want to keep the old version on your computer, you can install into the same folder as the old version.
3. You don't need to uninstall the old version beforehand if you're installing v1.0.6 or later. The installer will remove the old version from the list in the Add/Remove Programs list in the Windows control panel . If you're installing the upgrade in the same location as the old version, it will also delete that folder's contents before installing the new files. However, you may wish to delete the contents of that folder beforehand just to play it safe (do that if you're installing version 1.5).
4. Install the new version of Thunderbird, choosing your setup options from the Install Wizard along the way.
5. When finished, launch Thunderbird. It will automatically find and use your default profile and will disable any extensions that are not compatible.

Linux (tar.gz version)

1. Make a temporary backup of your profile(s).
2. Open a shell (terminal) and decide where you want to install the new version. Remove the old Thunderbird directory if you want to install over an older version; this does not remove your profile data.
3. Go to the directory you want to install Thunderbird, using the command: cd /path/to
4. Extract the downloaded Thunderbird "tar.gz" file: tar -xzvf /path/to/thunderbird-<version>-i686-linux-gtk2+xft.tar.gz
5. When finished, launch Thunderbird with the command: /path/to/thunderbird/thunderbird
6. Thunderbird should pick up your profile information automatically and be ready to use.

Hint to newbies: To avoid (mis)typing long file names, like Thunderbird's *.tar.gz file, merely type the first two or three letters, then press your tab key. The terminal program will fill the rest out for you.

Note: See Moving from Windows to Linux for information on how to use the package managers coming with many distributions for installing or upgrading your Thunderbird installation.

Mac OS X

1. Make a temporary backup of your profile(s).
2. Unpack and mount the "thunderbird**.dmg.gz". Double-click should do it all (if not already mounted).
3. Copy the "thunderbird.app" from the ".dmg" to your "Applications" folder, overwriting the existing one.
4. Launch Thunderbird. It should pick up your profile information automatically and be ready to use.

Troubleshooting

The common problems depend on which version you are trying to install.

Version 2

For information about common problems installing Thunderbird 2, see: Thunderbird 2.0 installation issues

Version 1.5

Most problems when upgrading to v1.5 are due to not deleting the contents of the Thunderbird program directory before installing the new version in the same location. Delete the contents of the Thunderbird program directory (after uninstalling Thunderbird using the control panel's add/remove programs), download a fresh copy of the setup program (in case it was really a corrupted download) and install it in the same directory. If you run into problems, try running Thunderbird in safe mode to temporarily disable any extensions/themes you may have added. Thunderbird tries to disable any incompatible extensions/themes, but not every extension/theme is well behaved. If that works, then you can try to identify the bad extension/theme and either uninstall or upgrade it.

If you can't get the Windows setup program to run, delete the contents of the Thunderbird program directory (after uninstalling Thunderbird using the control panel's add/remove programs) and download the appropriate win32.zip file. Note that this is a test build for developers, not the official released version, so it might differ from the released version in some ways. Expand it (specifying full pathnames) in the same Thunderbird program directory. You should be able to run that Thunderbird.exe. It should reuse the old registry entries for SimpleMAPI support and mailto: URLs which pointed to that directory. If not, try setting Thunderbird as the default email client.

See also

• Go back to an old version of Thunderbird