Microsoft Defender Quarantine is a feature that is integrated with Outlook to protect users from harmful emails and spam. It automatically holds suspicious emails in quarantine until the user can review them and decide whether to allow them to be delivered to their inbox or to delete them. You will receive a Spam Notification message notifying you of any messages that have been placed in quarantine. Any legitimate mail caught by mistake can be released directly from this message or the quarantine page (see details below).

Where to Handle Quarantined Email:

Legitimate messages placed in quarantine may be released to your inbox in one of two ways:

  • directly from the spam notification email message or
  • from the Quarantine page

You can check the quarantine portal anytime or whenever you are missing the expected email.

From the quarantine notification email message:

The following options will be available to you by clicking the respective links in the message, or you can choose to do nothing.

  • Review – view the quarantined email
  • Release – message is removed from quarantine and placed in your inbox.
  • Block Sender –you will no longer receive messages from the sender.
  • Do nothing – the message is left in quarantine and deleted automatically after 15 days.

From the Microsoft 365 Defender Quarantine page:

Quarantined email can also be handled on the Microsoft 365 Quarantine page.

  • Go to
    • A list of your emails in quarantine is displayed.
  • Click any message to select it, then choose from the options given (click the 3 dots to view all options):
    • Release email
    • View message headers
    • Preview message
    • Delete from quarantine
    • Block sender
  • Tip: Consider bookmarking to check your quarantine easily in the future.

Add a user to your Safe or blocked senders list

  • Log in to your Outlook Web Account, and click on the Settings icon in the top right corner of the screen.
  • Click View all Outlook settings
  • Select Mail, then Junk email
  • From this menu, you can search, add, and delete email addresses from your Safe Senders list. Please note that the Quarantine system will only use email addresses and not domains from your Safe Senders list. It’s also recommended to review your Blocked Senders list regularly to ensure that no legitimate emails are being blocked.

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