check before: 2026-01-01
Product:
Defender, Defender for Office 365, Defender XDR
Platform:
Online, US Instances, World tenant
Status:
Change type:
Admin impact, Feature update, Updated message, User impact
Links:
Details:
Summary:
Microsoft Defender for Office 365 will enhance quarantine by listing messages by individual recipients, improving backend durability and consistency. Rollout starts January 2026, completing by February. Admins must release quarantined messages per user. No changes affect end users; update internal processes accordingly.
Details:
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 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 February 2026 (previously mid-December 2025).
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 February 2026 (previously early January 2026).
Change Category:
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Scope:
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Release Phase:
Created:
2025-10-14
updated:
2025-11-14
Task Type
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Docu to Check
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MS How does it affect me
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MS Preperations
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summary for non-techies**
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Direct effects for Operations**
Quarantine Management Complexity
The change to list quarantined messages by individual recipients will increase the complexity of managing quarantined messages for administrators, as they will need to release messages for each user individually instead of in bulk.
- roles: IT Administrators, Helpdesk Support
- references: https://learn.microsoft.com/defender-office-365/quarantine-admin-manage-messages-files
Internal Process Updates
Without preparation, administrators may struggle with outdated internal documentation and processes, leading to inefficiencies and potential delays in message release.
- roles: IT Administrators, Compliance Officers
- references: https://learn.microsoft.com/defender-office-365/mdo-about
Configutation Options**
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IT Security**
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explanation for non-techies**
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** AI generated content. This information must be reviewed before use.
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change history
| Date | Property | old | new |
| 2025-11-14 | MC MessageTagNames | Feature update, User impact, Admin impact | Updated message, Feature update, User impact, Admin impact |
| 2025-11-14 | MC Summary | Microsoft Defender for Office 365 is enhancing quarantine for admins by listing messages by individual recipients, improving backend durability, and maintaining existing cmdlets with adjusted functionality. Rollout starts November 2025. No changes affect end users. Admins should update practices and documentation accordingly. | Microsoft Defender for Office 365 will enhance quarantine by listing messages by individual recipients, improving backend durability and consistency. Rollout starts January 2026, completing by February. Admins must release quarantined messages per user. No changes affect end users; update internal processes accordingly. |
| 2025-11-14 | MC Last Updated | 10/14/2025 01:25:21 | 2025-11-13T19:37:01Z |
| 2025-11-14 | MC Messages | 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 November 2025 and expect to complete by mid-December 2025. General Availability (GCCH and DoD): We will begin rolling out in early December 2025 and expect to complete by early January 2026. | 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 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 February 2026 (previously mid-December 2025). 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 February 2026 (previously early January 2026). |
| 2025-11-14 | MC Title | Microsoft Defender for Office 365: Enhancing the quarantine experience for administrators | (Updated) Microsoft Defender for Office 365: Enhancing the quarantine experience for administrators |
| 2025-11-14 | MC End Time | 02/02/2026 09:00:00 | 2026-03-30T10:00:00Z |
Last updated 1 day ago ago
