How can I use Thunderbird to keep regular offline backups of my Gmail account?

Question

I'd like to use Thunderbird to regularly download all the mail in my Gmail account via IMAP, so if something happened to Gmail or my internet connection is disrupted, I can still access all my mail.

My question is specifically about Thunderbird. Besides setting up the IMAP account, what else do I need to do in Thunderbird to ensure that all messages and attachments are synchronized locally as often as possible (not just when I "go offline" or manually synchronize).

Answer 1

1) Go to Tools / Options / Advanced / General / Config Editor

2) Search for mail.check_all_imap_folders_for_new and set to "true"

3) Go to Account Settings / Server Settings

4) Check 'Check for new messages at startup" and "check for new messages every x minutes"

5) Go to Account Settings / Synchronisation and Storage

6) Ensure "Keep Messages..." is enabled, with all folders checked in Advanced, and in Disc Space, "Synchronise all messages regardless of age"