Microsoft Defender for Office 365: Enhancing the quarantine experience for administrators
From Microsoft 365 Message Center Archive by Merill Fernando · Microsoft may not have sent this notice to your tenant.Rollout
Rollout dates are often only in the text. When Microsoft moves them, the change shows under "What changed".
Schedule dates changed in the text
Date phrases in schedule sentences differ between the versions this installation saw- Seen 9 Jan 2026
end of February 2026→ end of March 2026 - Seen 13 Nov 2025
early November 2025, mid-December 2025, early December 2025→ end of February 2026
Read from date phrases in Microsoft's text, not from notice metadata. A changed phrase can be a moved rollout, a new milestone or just rewording; "What changed" below shows which.
What the notice says
Microsoft’s text, safely structuredUpdated January 9, 2026: We have updated the timeline. Thank you for your patience.
We’re improving the quarantine experience in Microsoft Defender for Office 365 to deliver greater clarity, visibility, and ease of use for administrators. These updates include backend enhancements for improved durability and consistency as well as experience updates to list messages in quarantine by individual recipients to simplify navigation and management.
When this will happen
- General Availability (Worldwide and GCC): We will begin rolling out in early January 2026 (previously early November 2025) and expect to complete by end of March 2026 (previously end of February).
- General Availability (GCCH and DoD): We will begin rolling out in early January 2026 (previously early December 2025) and expect to complete by end of March 2026 (previously end of February).
How this affects your organization
- Who is affected: Administrators managing quarantined messages in Microsoft Defender for Office 365.
- What will happen:
- Quarantined messages will now be listed by individual recipient instead of grouped by multiple recipients.
- Backend enhancements will improve durability and consistency.
- Existing quarantine release cmdlets will all remain functional. Administrators should be cognizant that `ReleaseToAll` now applies to a single user as aggregation has been removed. Admins must release messages for each intended mailbox individually.
- No changes to end-user experience.
Screenshot 1 - Updated quarantine view showing individual recipients listed separately in the Recipient column:
Screenshot 2 - Existing quarantine view showing multiple recipients in the Recipient column:
What you can do to prepare
- Review your organization’s quarantine release practices.
- Update any internal documentation to reflect the new recipient-level view.
- Communicate this change to helpdesk or support teams as needed.
- Learn more:
- Microsoft Defender for Office 365 overview | Microsoft Learn
- Manage quarantined messages and files as an admin | Microsoft Defender for Office 365 | Microsoft Learn
Compliance considerations
No compliance considerations identified, review as appropriate for your organization.
What changed
Between archive captures, newest firstUpdated
November 12, 2025:January 9, 2026: We have updated the timeline. Thank you for your patience. We’re improving … 2026 (previously early November 2025) and expect to complete by end ofFebruaryMarch 2026 (previouslymid-December 2025).end of February). General Availability (GCCH and DoD): We will begin rolling out in early … 2026 (previously early December 2025) and expect to complete by end ofFebruaryMarch 2026 (previouslyearly January 2026).end of February). How this affects your organization:Who is affected: Administrators managing quarantined messages in …- Tags
Feature update, User impact, Admin impact→ Updated message, Feature update, User impact, Admin impact
Updated November 12, 2025: We have updated the timeline. Thank you for your patience. We’re improving the quarantine experience in Microsoft Defender for Office 365 to … happen:General Availability (Worldwide and GCC): We will begin rolling out in early January 2026 (previously early November
20252025) and expect to complete by end of February 2026 (previously mid-December2025.2025). General Availability (GCCH and DoD): We will begin rolling out in early January 2026 (previously early December20252025) and expect to complete by end of February 2026 (previously early January2026.2026). How this affects your organization:Who is affected: Administrators managing quarantined messages in …- Tags
- · first version seen
Learn more
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