Main menu

Office 365 Junk Email management

Last update: 11 April 2017

Office 365 E-mail system (Exchange) has a built-in spam filter system. This is tightly integrated with Outlook and the Junk Email folder in your mailbox.

The following section help you understand and manage this folder.

How does it work? In a nutshell...

All incoming and outgoing e-mails will flow through the Office 365 spam filter system.
Any anomalies are reported to the sender of the e-mail in a very detailed error report e-mail. An example of such an error message can be found here. See also below the section How to handle bounces.

Received e-mails which do contain any known virus will be deleted automatically and will not appear anywhere.

Received e-mails which are classed as spam will be delivered to your Junk Email folder.

The Office 365 system will learn from your decisions (see below) and maintains a list of known-to-you e-mail addresses (whitelist) and a list of deliberate rejected e-mail addresses (blacklist).

The Junk Email folder

The Junk EMail folder can be found in the mailbox list under the Mail view or Folder View.


The number between square brackets is the total number of e-mails in that folder.
You do not need to delete e-mails from that folder, the system will automatically delete these according to the Junk Email policy, default is after 30 days. You can check this in the Properties | Policy Tab.
Just click the Junk Email folder to open it.
Messages in this Junk Email folder will automatically suppress and block all potential harmful or unwanted contents, like pictures and links, which is clearly shown at the top of the selected message.

Move e-mail from/to my Junk Email folder

 When you find an legit e-mail in your Junk Email folder or unwanted e-mail in your Inbox, you can move it easily in a number of ways:

  1. Drag and drop the e-mail from/to your Junk Email to/from any other folder. This does not learn and the spam filter will filter same message again next time.
  2. Use the right-click menu on the message header, click Junk (below I explain each option):
    1. Block Sender. The e-mail address(es) in the e-mail will be added to your blacklist and the e-mail moved to the Junk Email folder.
    2. Never Block Sender. The e-mail address(es) in the e-mail will be added to your whitelist and the e-mail moved to you Inbox.
    3. Never Block Sender's Domain ( Same as above, but now you can whitelist an entire domain (e.g. everyone in
    4. Never Block this Group or Mailing List. Same as above for Group or Mailing Lists.
    5. Not Junk. The e-mail (in the Junk Email folder) is not Junk in your opinion and the e-mail address(es) will be added to your whitelist and the e-mail moved to your Inbox. This the option you will use most often to make the system learn and move your e-mail to your Inbox.
    6. Junk E-mail Options... Opens a menu with options to influence the working of the spam filter for your mailbox (see below).

Junk E-mail Options menu

This menu has the following Tabs:

  1. Options.
    Not sure yet, but these options are overridden by Office 365. So no use to change these.
  2. Safe Senders.
    Whitelisted e-mail addresses or domains ( for incoming e-mails. Entries in this list help to prevent e-mail going to the Junk Email folder.
  3. Safe Recipients.
    Whitelisted e-mail addresses or domains ( for outgoing e-mails. Entries in this list help to prevent e-mail being blocked by the outgoing spam filter.
  4. Blocked Senders.
    Entries in this list will cause e-mail always to go to the Junk Email folder. Sometimes it happens that an e-mail address is inadvertedly entered in this list (by right-click and Block Sender) and e-mails get filtered all the time. It will be good to check this list and remove this legit e-mail from it.
  5. International.
    Same as Options above, these seem to be overridden by Office 365.

How to handle bounces

When you receive a bounce message as shown in the example, there are a few things you can do to solve the situation.

  1. Read carefully the section under Error Details in the bounce message, that might give you the quickest insight in what is wrong.
    Example of an email classed as Spam:

    This message above shows "unsolicited", which means the receiving mail server's spam filter decided that the message is unwanted and blocked it. It also shows another address you could contact (This email address is being protected from spambots. You need JavaScript enabled to view it.).
    Another common problem when you recently migrated from an on-site Exchange server to Office 365 is cached (remembered) e-mail addresses in Outlook.
    The error looks like this when the remembered address is wrong (legacy type), which you can recognize in the highlighted first line:

    To solve this problem you must delete the remembered email addresses. When you start typing this email address in a new email, click the X button to the right in the presented list.

  2. Some of the reasons a spam filter are filtering messages are:
    1. Contents of the Subject line.
    2. Contents of the Message Body.
    3. Attachments, or types of attachments. Some filters do not like attachments with 2 dots, like This is considered to try to disguise malware.
    4. Your address is on a blacklist.
    5. The sending mail server is blacklisted (should not happen often or for a long period for Office 365 servers).
  3. To solve the communication block, try the following:
    1. Send a small test message to the same address.
    2. Ask the recipient to add your address or domain into their spam filter whitelist.
  4. If all else failed or there are unknown errors, please contact us by sending the bounce message to our HelpDesk e-mail address.