How to Kill off unwanted emails
1 Install SpamSieve plugins
To set up SpamSieve, first you must quit Mail. Then open SpamSieve and choose Install Apple Mail Plug-In from the SpamSieve menu. Now open Mail again and look in the Message menu for the new SpamSieve set of options.
2 Create Spam mailbox
Next, use the Mailbox menu to create a new mailbox called Spam (with a capital S), located on your Mac. (You can make this on the server so you can check spam from other devices, but this complicates matters a bit.)
3 Add a SpamSieve rule
Open Mail’s preferences, choose Rules, and add a new rule. The rule’s description absolutely must begin with ‘SpamSieve’ for this to work, but it can then contain whatever text you like, except for square brackets.
4 Configure the new rule
In the rule’s settings, change the From option to Every Message and set the action to move all your messages to the Spam mailbox. It won’t actually move every message; the SpamSieve plugin only touches rogue emails.
5 Prioritise SpamSieve’s rule
Click OK and choose Don’t Apply if asked, then move the SpamSieve rule to the top of the list of rules. This makes sure it’s run before any other rule, so you don’t accidentally prevent SpamSieve from doing its job.
6 Clean out old junk emails
Empty the Trash mailbox of any old emails, then delete anything in the Junk mailbox if you have one. It’s best to start out clean to avoid any confusion, but leave some fresh spam in the Trash for training purposes.
7 Turn off Mail’s filtering
Mail’s own junk filtering gets in the way of SpamSieve, so open the Preferences window, go to the Junk Mail tab, and uncheck the ‘Enable junk mail filtering’ option as well as ‘Trust junk mail headers’ if available.
8 Start training SpamSieve
Select some spam in the messages list and choose Message > SpamSieve – Train as Spam, so it knows what’s unwanted, then select good emails and pick SpamSieve – Train as Good. Ignore Mail’s own Not Junk button.