7.13.1 Why does the “Junk” mailbox appear in Apple Mail?
SpamSieve
With new installations of SpamSieve 2.9.45 and later, or if you have followed the Switching From the Spam Mailbox to the Junk Mailbox instructions, it’s normal for spam messages caught by SpamSieve to be moved to the special Junk mailbox.
Apple Mail’s Junk Filter
The Setting Up Apple Mail instructions have you turn off Mail’s built-in junk mail filter, so it will not put messages in the Junk mailbox.
Server Junk Filters
If your mail server has its own junk filter, it is normal for that filter to also put spam messages in the Junk mailbox. Because the messages are filtered at the server level, they never arrive in your inbox. Your Mac therefore does not see them as new messages, so it does not apply your regular Mail rules (or the SpamSieve rule) to them. Since these messages are not SpamSieve mistakes, you should not train them as spam. This is described more in the Separating Spam Caught by SpamSieve and Server Filters section.
The How should I configure the junk filter on my mail server? section has more information about server junk filters, how SpamSieve interacts with them, and how they can be turned off.
As of April 2015, Apple has made its iCloud server junk filter much more aggressive. It is putting a lot more spam messages (and also some good ones) into the Junk mailbox. It also deletes some messages so that they do not appear in any mailbox. This affects all icloud.com, mac.com, and me.com e-mail accounts. There is no way to turn off iCloud’s junk filter and prevent it from putting messages in the Junk mailbox, however SpamSieve can be configured to rescue good messages after the server filter has moved them to the Junk mailbox.
The Junk Bar and Messages Marked as Junk
It is normal for Mail to show a brown bar above some messages that SpamSieve or a server filter classified as spam. SpamSieve marks the messages as junk to protect you from Web bugs. Do not click the Not Junk button. If the message is not spam, you should instead choose SpamSieve - Train as Good from the Message menu.
