Migrate from Mozilla Suite or Netscape to Thunderbird
From MozillaZine Knowledge Base
You can migrate a profile (containing your mail, address books, account settings and preferences) from the Mozilla Suite or Netscape 7 to Thunderbird using one of the options given below. See Manually migrate part of the profile if you want to migrate a Netscape 4.x profile.
Migrate automatically when launching Thunderbird for the first time
When you install and launch Thunderbird for the very first time, the Import Wizard will ask if you want to import settings and mail from various mail clients, including Mozilla and Netscape. If you select one of these, it will automatically import your entire profile so that it is ready to use when Thunderbird starts up.
At present, this option is only available the very first time you launch Thunderbird on your computer. If you choose not to import anything via the Import Wizard at this point, Thunderbird will automatically create a blank, default profile for you, and once you have at least one profile, Thunderbird will no longer prompt you at start up if you want to import mail and settings from another mail client.
Migrate automatically by removing Thunderbird Profiles
This method is recommended only if you have been using Thunderbird for a very short time and you don't mind losing your account settings and access to messages you've already downloaded.
If you "missed your chance" to import your Mozilla or Netscape profile via the Import Wizard and you would like to do so later, you can bring up the Import Wizard again by exiting Thunderbird, using the Thunderbird Profile Manager to delete all of the profiles listed, exiting the Profile Manager, and then launching Thunderbird again. Warning: When deleting a profile, do not use the "Delete Files" option if you created the profile by choosing your own folder location. Data loss can occur if the chosen folder already contained data, so use the "Don't Delete Files" option instead.
If that fails to bring up the Import Wizard, or if you don't wish to use the Profile Manager, exit Thunderbird and then delete (or rename) the "Thunderbird" folder that contains the "Profiles" subfolder and the "profiles.ini" "pluginreg.dat" and "registry.dat" files (for example, in Windows XP, delete the C:\Documents and Settings\<username>\Application Data\ "Thunderbird" folder) and then launch Thunderbird.
Manually migrate a profile
Another way to migrate an entire profile from the Mozilla Suite or Netscape 7 is to do it manually. See here for detailed instructions. The main problem with migrating the entire profile this way is it does not delete any of the browser specific directories/files and all of the extensions/themes will be incompatible.
Manually migrate part of the profile
Instead of migrating the entire profile, you could create a new profile and then migrate just your message folders, address books , message filters and any saved passwords to it. Don't transfer your account settings, extensions or themes. See this article.
Those instructions also work with Netscape 4.x profiles. Netscape 4.x used .snm files as the index files, rather than .msf files. Thats not an issue since there is no need to transfer the index files (Thunderbird will build new ones). It uses the same format as Thunderbird for mbox files (mail folders) , address books and saved passwords but uses the old Thunderbird format for message filters. You should be able to reuse the old message filters but probably won't be able to use any of the new features added to message filters. Its recommended you create new message filters.
Migrate using the MozBackup utility (Windows only)
The MozBackup utility is designed to back up and restore profiles for the Mozilla Suite/Netscape 7, Firefox, and Thunderbird. Although it is not intended for migrating profiles from the Mozilla Suite/Netscape 7 to Thunderbird, it does seem to work for this purpose: in other words, use MozBackup to back up a Mozilla Suite/Netscape 7 profile and then use it again to "restore" this backed-up profile over an existing Thunderbird profile. See here for further information on using the MozBackup utility.
Migrate additional profiles
If you want to migrate additional profiles you need to do it manually. You can move address books between profiles by exporting them as .LDIF files from one profile, and then importing them in another. You can move the folders using the ImportExportTools extension.
Launching the Import Wizard for a new profile
You can migrate several profiles using these command line arguments (replace ./thunderbird with your method of calling thunderbird):
./thunderbird -createProfile ProfileName ./thunderbird -P ProfileName -migration
The first command creates a new Thunderbird profile (which can also be done using the Profile Manager) and the second command launches Thunderbird with the Import Wizard for that profile.
Important: Profile names are case sensitive. Also, if the profile name you wish to use contains a space, it must be created via the Profile Manager and it must be enclosed in double quotes in the second command (e.g.,
On Windows, you can also run the migration command for the new profile by using a desktop shortcut to the new profile, which you have modified by adding the
Thunderbird 11.0 and later
The direct migration/importing of old profiles from Netscape 6.x/7.x, Mozilla Suite 1.x, or SeaMonkey 1.x has been removed with Thunderbird 11.0 (this also applies to SeaMonkey 2.8 and later when trying to import such profiles). To migrate those, use either Thunderbird 3.x or SeaMonkey 2.0 to import the old profile, then update to the most recent Thunderbird version from there. As always, make sure to have a profile backup before getting started so that you can roll back to the original state.