Thunderbird provides the ability to archive messages - that is, to move them from the default folders to archive folders without deleting the messages altogether. This makes it easy to organize archives and move them to a backup device. Messages can only be archived manually, not automatically. Archived messages are indexed by Thunderbird's search.
I found a work around to Auto Archive Messages and Posted the info at the Bottom of this Post... Don
The location of archived messages can be configured individually for each email account. In Tools | Account Settings, select the desired email account in the left panel, and then select the Copies & Folders setting. In the Drafts, Archives and Templates section of the setting page, use the settings in Keep message archives in to set the desired location.
To archive a message (that is, to move it from its current location to the location specified in the preference above), click on the message to select it, then either select Archive from the right-click context menu, or Archive from the Message drop-down menu. (The keyboard shortcut for the Archive function is the letter "A".)
When archiving messages, Thunderbird will locate the archived messages in different folders. This is to prevent mail data files from becoming so large that they are unwieldy for searching and indexing, and also to enable off-loading and backup of messages. By default, when you archive messages Thunderbird will creates an archive directory for the current year. These files are created according to the following directory and file name convention:
... where, in the example above, the archived messages are from 2009.
The frequency of the archiving is based on the mail.server.default.archive_granularity setting, which is set to "1" (yearly) by default. To use just a single folder, set the value to "0". To enable monthly archiving, change the value to "2". (To change preferences settings, select "Thunderbird | Preferences | Advanced | Config Editor" (or, on Windows, Thunderbird | Tools | Options| Advanced | General | Config Editor).)Go there...
Auto Archive Messages
You can set up a filter to apply every time you check your e-mail that moves all e-mail older than a set number of days (in my case I set it at 30) to the Archive.
To create a filter go to "Tools", "Message Filters", "New".
In the box at the top give it a useful name such as "Auto-archive".
In the second box you can select when to run it, usually either manually or whenever you check your mail.
In the next section down where it says "Subject" use the drop down box to choose "Age In Days", choose "is greater than" for the middle box and put a number for the days in the last box (30, 60 whatever).
The next section specifies what to do with the mail that fits the filter. In my case I have picked "Move Message to", "Archives on ??? Account". You can choose any folder you want and you can also add another action to put another copy in a local folder so you have two archived copies.
Press "OK" and the filter will run every time you check your e-mail.
In this case my filter now reads:
"When checking mail or manually run, if age in days is greater than 30, move message to Archive on ??? Account plus Copy message to Archive on Local Folders".
It won't sort it into the years but it is easy enough to open the main archive folder, "select all" then tap the A key. All the archived e-mail will then end up in the right year sub-folder.
Hopefully somebody will make "Archive" a Filter action and the whole thing can then be made totally automatic.
I setup my Filter like stated above and Manually Archived my Messages one time and will see how it works...