Microsoft Defender for Office 365: Quarantine asynchronous update

Microsoft Defender for Office 365 is introducing a new way of interacting with quarantined messages through an asynchronous approach. Previously, quarantine operations were carried out in a synchronous model on the technical execution side.

Note: This change is a major step towards introducing partial string search functionality and 1,000 message bulk operation support in quarantine.

This message is associated with Microsoft 365 Roadmap ID 93303.

When this will happen

Standard: will begin rolling out in late June and be completed by mid-July.

Government: will begin rolling out in late July and be completed by early August.

How this will affect your organization:

Previously, an Admin from Contoso.com could release a quarantine message to a User in Tailspintoys.com. However, to eliminate the risk that comes with such behavior we will be disabling it. Moving forward an Admin will need to download the item from quarantined with the password protected feature and use the download item for the specific workflow they want to accomplish. Please note that we will continue to support an Admin release to recipients who are in the same organization as the Admin.

Release to recipient in external organization disabled:

Release to recipient in external organization View image in new tabShare email screens:

We will be introducing two new quarantine statuses namely “Preparing to release” and “Error.” The “Preparing to release” status will indicate that the messages are in the process of being released while the “Error” status will indicate that a message release has failed, and the user needs to retry.

Share emailView image in new tabNew quarantine status:

New quarantine statusView image in new tabWhat you need to do to prepare:

The goal for this communication is mostly for informational awareness. You may consider updating your training and documentation as appropriate.

Message ID: MC384326


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I've been working with Microsoft Technologies over the last ten years, mainly focused on creating collaboration and productivity solutions that drive the adoption of Microsoft Modern Workplace.

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