The list of 'old' messages will appear in the lower pane. Define the search criteria as 'Age in Days is greater than 90' (or however many days you want).Make sure that the checkbox for 'Search subfolders' is checked.If you are using Thunderbird's Global Inbox with multiple POP accounts, you can select Local Folders as the account. Where it says 'Search for messages in', select 'choose this folder' for the account whose messages you want to archive.Go to the 'Edit' menu and choose 'Find -> Search Messages.'.Create a new folder in Local Folders and call it 'Archive'.Instead of individually selecting messages to be archived, you could use an advanced search to quickly find all messages in any account(s) and/or folder(s) 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. Starting with Thunderbird 5.0 you can disable the built-in archive support on a per-account basis by unchecking 'Keep message archives in' in Tools -> Account Setting -> Copies & Folders. Any account which doesn't have specific settings will inherit from those preferences: In addition to the per-account settings, you can set the defaults for the following preferences using the Config Editor. The folder tree shows an example for the resulting folder structure and is not derived from any of your own folders. A checkbox to keep the structure of the original folder in the 'Archives' folder, which are arranged underneath the optional year and month folders.A single (flat) arrangement, grouping by year (default), or by year and month.

This add-on is an improved version of another add-on called 'Autoarchive'.Each account has a 'Archive Options' button in Tools -> Account Settings -> Copies & Folders (except Gmail as they don't support child folders ) that provides several ways to organize the archive folders: Attention Use the AddOn on your own risk! Some (few) users reported data loss. Open some instructions under Report Bugs under.

You can use it for example if you want to archive your mails from an IMAP account (where you usually does not have so much space) to your local computer.

This add-on helps you and archives your messages automatically after the time you have configured. Thunderbird can archive messages but you have to do it manually for every message.

Archiving thunderbird email