What is Thunderbird Application and all The Related Info Mentioned Here!


What is Mozilla Thunderbird?

Mozilla Thunderbird is an open source and cross platform email, newsgroup, and chat client which is developed by Mozilla foundation. This emailing client is enriched with features such as saved search options, quick search folders, message grouping, labels, advanced message filtering etc. You will find this application incorporating spam filter, a white list based on address book and many more aspects. With extensions, addition of features through the installation of XPInstall modules via add-ons websites also features an update function. You can choose plenty of themes as per your wish to change the look. It supports POP, IMAP, and LDAP address completion. Its specialty is its ability to run on multiple OS such as Windows, Linux, and Mac.

thunderbird information

Thunderbird Email Database Location in Windows

In Windows Thunderbird stores email databases in the profile folder which is located in the following mentioned location:


Here, input the %AppData% first in the file explorer and then move to the next folder. Also, make sure to adjust Windows Explorer settings in order to show hidden objects. Because the Application Data folder is hidden with the default system settings.

XXXXXXXX.default - here X refers to any letter or number.

Within the profile folder, you must look to search a subfolder for each of the mail accounts and the other one for 'Local Folders'. Each of these folders comprises of files with the names matching your Thunderbird folder names. For example: Inbox, Drafts, etc. These files are no extension mailbox files.

Another Way to Locate the Thunderbird Database location manually:

  1. In Mozilla Thunderbird, click on “Local Folders” and then hit the “Settings” button on the right window.
  2. The “Local directory” displays the exact location where the Thunderbird files are kept.
  3. nndbase.txt – nickname file
  4. For other mailboxes, look for the local directory option in “Server Settings”.

Thunderbird File Formats

  • No extension files – MBOX files that store email messages
  • MSF Files – index files that store summary of emails
  • SBD folders – Folders that store mailbox files and are used for subfolder hierarchy

Each of the Thunderbird mail folder stores in two files which are named after the mail folder name such as:

File with no extension consisted of email messages in the plain text format, one after the other. This file is actually larger in size than MSF which is the index file.

The corresponding MSF file comprise of mail folder indexes and preference data. Thunderbird shows the part of message to be displayed, the arrangement of messages within the folder, and many more, entirely based on the MSF file info. MSF file has no email messages. Thunderbird will reconstruct MSF files as per the requirement if they are missing.

About Thunderbird SBD folders

Folders which have SBD file type are basically designed for a subfolder management. Here SBD is shortened for SubDirectory. They are used for holding a hierarchy of all the mail folders. When you create a new folder within some of the existing for the very first time, Thunderbird automatically creates a SDB folder for storing email data of child folder. Name of the folders are according to the parent folder to which child belongs.

As an example, if you create a mail folder under Inbox folder, then mailbox file as well as corresponding .msf file of the child folder will get stored in.

%USERPROFILE%\Application Data\Thunderbird\Profiles\XXXXXXXX.default\Mail\Local Folders\Inbox.sbd

Extensions in Mozilla Thunderbird

Many people argue that Thunderbird does not provide features that several other email clients provide, thus hurting user productivity. This can be countered with the help of extensions and add-ons that can increase the features of Mozilla Thunderbird. A user can install the add-ons by doing the following steps:

  1. Hit the “Alt button” on the keyboard and go to “Tools” menu.
  2. Now, select the “Add-ons” options.
  3. Here, you can search for extensions choose different themes and much more.

Some of the most common extensions in Thunderbird are Lightning, ImportExportTools add-on, Enigmail, etc.

Being one of the most common email clients used all over the globe, Mozilla Thunderbird has a large user base. The users often come across common Thunderbird errors caused by bugs, human mistakes and hardware-software related issues. Some of these issues are:

Note: While Mozilla Thunderbird is a great email client, many users still move to other email platforms to be more scalable and productive. If that email client happens to be MS Outlook, you can view the article to convert Thunderbird mailbox to PST file that Outlook supports.