Move Spam to the Junk Folder Automatically in Mozilla Thunderbird

After you have trained the spam filter in Mozilla Thunderbird for a while and are satisfied with its classifications, you can reap its biggest benefit. Mozilla Thunderbird can automatically move all the junk out of the way of your Inbox automatically and dump it in the Junk folder.

Make sure, though, that you visit the Junk folder from time to time and that you correct false classifications both in this folder and in your Inbox with pedantic meticulousness.

Move Spam to the Junk Folder Automatically in Mozilla Thunderbird

To make Mozilla Thunderbird file junk mail to a separate folder automatically:

  • Select Tools Options > Security from the menu.
  • Click the Junk category.
  • Make sure When I mark messages as junk: is checked and that the radio button is set to Move them to the account's "Junk" folder.
  • Click OK.

Set Per-Account Rules

Override the global junk-handling configuration by selecting Tools > Account Settings > Junk Settings from the menu. Thunderbird supports per-account rules for handling junk messages. In the Junk Settings panel, specify where to put incoming spam — the default "Junk" folder, or any other folder of your choice — for each account you've set up in Thunderbird. Optionally, you can configure each account to delete spam older than a configurable amount of time (the default is 14 days). 

Automatic Deletion of Spam

Thunderbird will not automatically remove spam from your junk folders unless you've set a per-account rule. Instead, your email provider's rules govern. For example, Gmail won't automatically delete junk mail, but you can create a filter while logged directly into Gmail that will delete junk mail for you. This setting is independent of Thunderbird. 

You can, however, manually empty an account's Junk folder at any time — whether in Thunderbird or while logged into the account using a different program or web interface.

Junk Mail Best Practices

No one likes getting spam, but managing spam well takes some patience:

  • If your email provider offers a machine-learning algorithm to "train" it how to clean your inbox, you'll need to spend a few weeks or months up front helping the algorithm to correctly classify messages. Setting junk flags or separate "spam" and "ham" flags tell your email provider's anti-spam rules what you want to see and what you don't. Over time, these tools offer exceptional accuracy — at the price of the up-front training investment.
  • No junk-mail scanner is perfect. Accordingly, you should set your email programs to retain junk mail until you have the chance to review it manually. 
  • Be careful what you flag. If you get a newsletter you no longer want, unsubscribe from it instead of marking it as junk, because some email providers will "report" spam to clearinghouses. One or two false reports of junk could be enough to put a small business's email server on blocklists, which then affect other users. 
  • Never reply to junk mail — all you'll do is get more of it in the long run.
  • Consider turning off HTML views of your inbound email. Some messages contain tracking pixels that signal a remote server that a human being has opened and viewed the message, even if you ultimately sent it to the Junk folder. The fact that an email address is "live" can invite significantly more spam later.
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