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Microsoft Defender Quarantine

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.


  • Provides an extra layer of protection from phishing and spam for our campus.
  • Microsoft Defender Quarantine empowers end users to release messages they previously would not have seen. 
  • Users have control over their own safe senders and blocked senders lists that can be edited at any time. 

Watch OIT's Microsoft Defender Quarantine Overview and Tips video to learn more: 

Who can get it 

All faculty, staff and students using Microsoft Exchange for email automatically have Microsoft Defender Quarantine enabled.

How to check quarantined emails

  • Go to and login with your IdentiKey username and password. Please note: You can also release or block emails directly from a Quarantine notification email message. 
  • Review the list of emails that have been quarantined.
  • Click Preview to see the content of the email. 
  • Click Release to move the email to your mailbox.
  • Click Delete to remove the message from your quarantine.

Tip: Consider bookmarking to easily check your quarantine in the future. 

The deleted items folder retention period is 30 days. After that, messages are automatically removed from the folder. Items that have been automatically removed from the Deleted Items folder are retained for 30 days before being permanently deleted. 

Interested in more detail and screenshots of this process? Visit the Microsoft Defender Quarantine - Release and delete emails tutorial. 

Add a user to your Safe or blocked senders list

  • Log in to your Outlook Web Account, 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.

Interested in more detail and screenshots of this process? Visit the Microsoft Defender Quarantine - Edit your Safe and Blocked senders list tutorial. 

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