From MozillaZine Knowledge Base

This article was written for Thunderbird. None of the extensions mentioned in this article support other applications, but the other solutions may work with the Mozilla Suite or SeaMonkey.

Thunderbird does not have a built-in feature for archiving e-mail. Some alternatives or workarounds are listed below.

Using the Buttons! extension

The Buttons! extension provides numerous buttons that you can add to your Thunderbird toolbar, including an "Archive!" button. Once you've configured the extension, just select one or more messages in the message-list pane and then click the Archive! button. Those messages will be filed in the archive folder that you've specified. Users of Gmail will find this very similar to the way Gmail's archiving feature works. However, archiving with the Buttons! extension is more flexible because you can set up the extension to use any archive folder of your choice, and you can also specify more than archive folder (with one set as default).

Using searches

Instead of individually selecting messages to be archived, you can instead use an advanced search to quickly find all messages in various folders and subfolders that meet your search criteria (e.g., older than 90 days), and then move those messages all at once to an archive folder of your choice. Here's one possible way to do this:

1. Create a new folder in Local Folders and call it "Archive".
2. Go to the "Edit" menu and choose "Find -> Search Messages...".
3. Where it says "Search for messages in", select "choose this folder" for the account whose messages you want to archive. If you are using Thunderbird's Global Inbox with multiple POP accounts, you can select Local Folders as the account.
4. Make sure that the checkbox for "Search subfolders" is checked.
5. Define the search criteria as "Age in Days is greater than 90" (or however many days you want).
6. Click the "Search" button. The list of "old" messages will appear in the lower pane.
7. Select all messages listed in the search results, and use the "File" button to move them all to the "Archive" folder you created in step 1.
8. If you have more than one mail account that you want to archive, repeat the above steps for each additional account. (If all your accounts are using the Global Inbox, you will not need to repeat the above steps.)

Note:

• After step 6 above, Thunderbird users can also make a Saved Search folder so that in the future this same search (steps 2-6) can be performed with a single click. If you want to exclude certain folders from being searched, just right-click on the Saved Search folder, choose "Properties...", click the "Choose" button, and (de)select folders as desired.

• The above procedure will put all of your archived mail into a single folder, and it thus will not preserve your folder structure.

Using the ImportExportTools extension

The ImportExportTools extension can be used to import or export messages (.eml files) or folders (mbox files). It can also export all of the messages in a folder as either HTML or plain text files, plus an index. This extension used to be called the MboxImport extension.

You could archive individual messages as .eml file or folders as mbox files, save them somewhere else, delete the original, and then import them again later on if needed. If its more convenient you could use the Archive! button from the Buttons! extension to archive messages as .eml files and just use this extension to import them. You could also use the MboxViewer to view archived folders if you didn't want to import them again.

Using MozBackup (Windows only)

The MozBackup utility can be used to back up your entire Thunderbird profile, including all downloaded mail, and it will preserve the folder structure of your mail when restored. Here's one way you could use MozBackup for archiving:

1. Compact folders and then exit Thunderbird.
2. Launch MozBackup and use it to make a backup of your Thunderbird profile. (Detailed instructions are here.)
3. Restart Thunderbird.
4. As described in the "Using searches" section above, do an advanced search of your mail, but instead of creating an "Archive" folder (step 1) and filing all the old messages into it (step 7), simply delete all the old messages. These messages will all have been saved in in the backup you made with MozBackup, so it shouldn't cause any harm to delete them from your active Thunderbird profile.

Note:

• If "archiving" your mail in this way, there will be some overlap between the mail in the MozBackup backup and the mail in your active Thunderbird profile, since MozBackup will back up all downloaded mail in the profile regardless of age.
• IMAP users: If you store your messages in remote folders then MozBackup will only back up the headers unless you download a copy of the messages first. One way to do that is to right-click on the remote folder, select "Properties -> Offline" and then press the "Download Now" button. If you used "Tools -> Account Settings -> Offline & Disk Space" instead that doesn't just download a snapshot of the remote folder, it keeps a local copy synchronized with the remote copy. In both cases you need to use "File -> Offline -> Work Offline" to access those folders within Thunderbird.

Using Mbox2xml (Windows only)

Mbox2XML is a Windows application to backup one or mbox files (folders) in a .XML file that can be displayed using a modern browser such as IE, Firefox or Opera. It converts any HTML messages to plain text. The user has the option to include attachments. It uses UTF-8 encoding, which provides support for most character sets.

It can be useful for archiving messages so that you can read them without a email client. However, unlike most of the other alternatives you can not restore its archived messages in Thunderbird.

Printing to a PDF file

PDFCreator is a Windows utility that lets you save a message as a .PDF file by printing it, or combine several messages into one .PDF file. Combining several messages requires you to print a message to the PDFCreator printer, select wait, print the next message(s) and on the last message select the messages you want to merge, and press the Combine button.

Note: If your PC supports Data Execution Prevention (DEP) don't press the Options button or use File -> Options. All that appears to do is let you save settings in a .ini file rather than the registry so its no real loss.

Linux supports several different ways to print a message as a PDF file such as cups-pdf or Kprinter .

Using IMAPSize (IMAP accounts, Windows only)

If you store your messages in remote folders you could use IMAPSize to incrementally back up messages from one or more folders or accounts as .EML files in a directory on your hard disk and then back up those files normally. An incremental backup means that the messages that have already been backed up will not be backed up (downloaded) again. You can back up using either a batch file or the GUI. The Account/RestoreBackup menu is used to restore backups.

Using the Autosave extension

The Autosave extension lets you specify what messages should be automatically saved as .eml files when sent or received. It doesn't have a GUI, you need to modify preferences per this thread. It only supports version 0.5 through 1.0 but it will work with 2.* if you disable the version check per this article. The extension is powerful, it even supports regular expressions in determining what messages get saved. However, the developer warned that the extension was not suitable for a production environment (insufficient testing) and the developer abandoned work on all of his extensions several years ago and hasn't been heard from since.

Other information

• Bug 93094: Add an archive feature to Netscape mail.
• Mail utilities