The iCloud uses different techniques automatically detect and block junk mail before it reaches your Inbox. The silent iCloud spam filter does keep some spam out of your inbox/junk mail folders entirely behind the scene. However, at times there are false positives mails that land to your spam folder, and also some junk mail may still reach your inbox. You can always manage the amount of junk mail that you receive.
First of all, if you think a message may be a spam mail, don’t open it. Opening a spam mail can encourage more junk mail. Therefore, if you think a mail you have received has no clear reason to be in your inbox, or is too suspicious, you can always delete them or you can use Mail app to mark messages as junk and aid the iCloud spam filter so that later messages from the sender are automatically marked as junk.
In iOS 7 or later:
- Open the message
- Tap the flag icon at the bottom
- Then tap “Move to Junk”.
In OS X:
- Select the message
- Click the Junk (thumbs down) icon in the Mail toolbar.
- Select the message
- Then click the flag icon
- Choose “Move to Junk”.
- Or just drag the message to the Junk folder.
These are the iCloud spam filter settings for iCloud OS X, iOS 7 and icloud.com.
Furthermore, you can always report a junk mail. You can complement iCloud spam filter by manually reporting junk messages. You can do this by forwarding a message as an attachment to email@example.com.
To prevent junk mail from being sent to your primary iCloud email address, you can always use an alternate email for purposes other than emailing, such as for online registrations, or joining mailing lists, for instance.
And, in false-positive cases when the iCloud spam filter marks your legitimate email from friendly source as junk and blocks from reaching your inbox, first thing to do is to check your junk folder. To check your junk folder :
- Choose the Mail application, then click the Junk folder in the sidebar.
- Select a message, then click the ‘Not Junk’ button in the top right of the message window.
[The message is moved to your inbox. Subsequent email messages form the same sender are no longer automatically marked as junk.]
Emails messages in the junk folder are automatically deleted after 30 days. Therefore, check the Junk folder periodically for email messages that were marked as junk mistakenly.