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Backup of Thunderbird

Method 1: Backing up the entire profile

This method will back up all of your profile data (such as passwords, bookmarks, mail, preference settings and installed extensions and themes) for each profile in the default profile location, as well as the registry.dat or profiles.ini file that records the profile location. All profile data will be backed up together, at once.

  1. (Optional) Clear the cache in Firefox (Tools > Options > Privacy > Cache > Clear) and Mozilla Suite (Edit > Preferences > Advanced > Cache > Clear Cache) and compact the mail in Thunderbird and Mozilla Suite to reduce the size of the backup.
  2. Exit your Mozilla Suite Firefox or Thunderbird program. (Mozilla Suite on Windows: exit Mozilla Quick Launch if enabled). Make sure no Mozilla Suite/Firefox/Thunderbird processes are still running.
  3. Open the file explorer on your system and find the folder that contains the "Profiles" folder and the files "pluginreg.dat" "registry.dat" and/or "profiles.ini" (some of these files may not exist).
    • For Thunderbird: Copy the "Thunderbird" folder.
    • For Mozilla Suite: Copy the "Mozilla" folder.
    • For Firefox: Copy the "Firefox" folder.
  4. Copy (but not move) the "Thunderbird" "Mozilla" or "Firefox" folder to the backup location. For example, place the backup folder inside your home directory (Windows users: "My Documents" is your home directory) or copy it to another drive.
Unsupported: This freeware has been tested and seemed to work well (Windows only):

In Thunderbird 3.x

Unless you are an advanced user its generally preferable to use an application to import or export a folder since that typically sanitizes the file to minimize any incompatibilities. If you use IMAP's optional offline mode to create a local copy of remote folders, think ahead about how you will deal with any potential synchronization issues. To manually import/export mbox formatted files:

  1. Identify the e-mail account you want to use for the imported mail. You can use the Local Folders account, or some other account, or you can create a new account specially.
  2. In Account Settings, go to the Local Folders account's main page to find its Local directory path. Or, to import the folder into some other account, go to the account's Server Settings page to find its Local directory path. Make a note of the path.
  3. Exit Thunderbird or Mozilla Suite.
  4. Back up your profile or Mail directory, especially if you plan to overwrite existing mbox files.
  5. Copy the mbox files you are importing to the local directory that you identified in step 2. For example, copy "Inbox" (not Inbox.msf) to the account's local directory.
    Note: If you want to keep the existing mbox file of the same name in the new location, rename the file you wish to import before copying it over. For example, rename "Inbox" to "InboxOld" and "Sent" to "SentOld".
  6. Open Thunderbird or Mozilla Suite. As it starts up, the application automatically discovers new mbox files and makes them into folders. A folder for each file you copied should be displayed.
  7. Open each folder and verify that it contains the correct number of e-mails, that they are readable, and that you can open attachments. Sometimes, differences between mbox formats cause multiple emails to be combined into one larger e-mail or can make some e-mails unreadable.

Troubleshooting is beyond the scope of this article, but if you examine the mbox technical links and the links to importing specific programs, you may find helpful information.

IS&T Contributions

Documentation and information provided by IS&T staff members

Last Modified:

February 28, 2012

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