Part 1 : Activating the Junk Mail Controls

1. Go to "Tools" > "Junk Mail Controls"

2. You will be presented with this window. From the dropdown list, choose the email account you want to activate the Junk Mail Controls.

3 Click the "Adaptive Filter" tab and check the checkbox for "enable adaptive junk mail detection".

4 If you would like to implement Junk Mail Controls for your other email accounts, repeat the above steps.

5 Click the "OK" button when done.

Part 2 : Training the Junk Mail Controls

Thunderbird uses "Bayesian filtering", a popular filtering mechanism which learns to differentiate spam email from legitimate email. This filtering method requires you to train the mail client what is spam, and what isn't. To begin, you need to mark messages that you've received as either "junk" or "not junk". It is important that you mark both types of messages rather than just marking the ones that are junk mail. There are various ways that you can mark messages:

• Right-click on a message and choose "Mark -> As Junk" (or "As Not Junk")
• Select a message From the "Message" menu, choose "Mark -> As Junk" (or "As Not
  Junk")
• Select a message and click on the "Junk" icon on the toolbar
• Select a message and click on the "Junk Status" column in the message-list pane (which will show a small "Junk" icon if the message is marked as junk)
• Select a message and type "J" (for Junk) or "Shift+J" (for not Junk)

Initially, the automatic junk mail detection for incoming messages may not be very accurate because it has not been trained very much. Therefore, you should check your Junk folder every now and then to see if any non-junk messages have been accidentally detected as junk. After the initial training period, the Junk Mail Controls should be quite effective in detecting unwanted junk emails.