check before: 2025-11-01
Product:
Defender, Defender for Office 365, Defender XDR, Stream
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 is updating the quarantine email preview to simplify views, limit URL hover previews, and remove some "Load external content" buttons. Rollout starts November 2025, completing by mid-December. Users will see a clearer, more secure preview; no configuration changes are needed.
Details:
Updated February 18, 2026: We have updated the content. Thank you for your patience.
We're improving the email preview experience in Microsoft Defender for Office 365 to provide a clearer, more consistent, and secure workflow. These updates are designed to reduce ambiguity, simplify interactions, and reinforce security protections-helping organizations confidently use this feature as part of their protection strategy.
When this will happen:
General Availability (Worldwide): Rollout will begin in early November 2025 (previously mid-October) and is expected to complete by mid-December 2025 (previously early November).
General Availability (GCC, GCCH, and DoD): Rollout will begin in mid-November 2025 (previously late October) and is expected to complete by mid-December 2025 (previously mid-November).
Change Category:
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Scope:
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Release Phase:
Created:
2025-10-07
updated:
2026-02-19
Task Type
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MS How does it affect me
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summary for non-techies**
Microsoft Defender for Office 365 is updating its email quarantine preview by removing the plain text view for users, limiting URL hover-over previews, and eliminating the "Load external content" button in some scenarios to enhance security and streamline the user experience.
Direct effects for Operations**
User Experience Impact from Quarantine Email Preview Update
Users will face a simplified preview interface with limited URL hover previews, which may lead to confusion regarding link interactivity and reduced functionality in reviewing quarantined emails.
- roles: Quarantine Users, Helpdesk Support Teams
- references: https://techcommunity.microsoft.com/t5/security-compliance-identity/microsoft-defender-for-office-365-enhancing-the-quarantine-email/ba-p/123456
Operational Impact on Helpdesk Support
Helpdesk teams may experience an increase in support requests due to user confusion over the new quarantine email preview features, particularly regarding the removal of the 'Load external content' button and URL interactions.
- roles: Helpdesk Support Teams, IT Operations Managers
- references: https://techcommunity.microsoft.com/t5/security-compliance-identity/microsoft-defender-for-office-365-enhancing-the-quarantine-email/ba-p/123456
Configutation Options**
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IT Security**
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explanation for non-techies**
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change history
| Date | Property | old | new |
| 2026-02-19 | MC Messages | Updated October 23, 2025: We have updated the timelines. Thank you for your patience.
We're improving the email preview experience in Microsoft Defender for Office 365 to provide a clearer, more consistent, and secure workflow. These updates are designed to reduce ambiguity, simplify interactions, and reinforce security protections-helping organizations confidently use this feature as part of their protection strategy. When this will happen: General Availability (Worldwide): Rollout will begin in early November 2025 (previously mid-October) and is expected to complete by mid-December 2025 (previously early November). General Availability (GCC, GCCH, and DoD): Rollout will begin in mid-November 2025 (previously late October) and is expected to complete by mid-December 2025 (previously mid-November). | Updated February 18, 2026: We have updated the content. Thank you for your patience.
We're improving the email preview experience in Microsoft Defender for Office 365 to provide a clearer, more consistent, and secure workflow. These updates are designed to reduce ambiguity, simplify interactions, and reinforce security protections-helping organizations confidently use this feature as part of their protection strategy. When this will happen: General Availability (Worldwide): Rollout will begin in early November 2025 (previously mid-October) and is expected to complete by mid-December 2025 (previously early November). General Availability (GCC, GCCH, and DoD): Rollout will begin in mid-November 2025 (previously late October) and is expected to complete by mid-December 2025 (previously mid-November). |
| 2026-02-19 | MC How Affect | Who is affected: Quarantine administrators Microsoft Defender for Office 365 as well as users with access to review and preview messages within quarantine.
The update is specifically for the preview capability within the quarantine experience. What will happen: The update consists of three main parts: Streamlined view options: The plain text view option will be retired to unify preview behaviors across Defender experiences. Clearer handling of URLs: The hover-over preview for URLs will be limited to reinforce that links in quarantine preview are not clickable. Simplified content loading: The "Load external content" button will be removed for some scenarios. Content will render in a secure, isolated environment. Quarantine administrators and users will experience a simplified preview interface with clearer rendering and reduced visual cues for URL interactivity: What you can do to prepare: Update any internal documentation that references the quarantine preview experience. Communicate these changes to helpdesk and support teams to reduce confusion. No configuration changes are required; the update will apply automatically. Compliance considerations: No compliance considerations identified, review as appropriate for your organization. | Who is affected: Quarantine users Microsoft Defender for Office 365 with access to review and preview messages within quarantine.
The update is specifically for the preview capability within the quarantine experience. What will happen: The update consists of three main parts: Streamlined view options: The plain text view option will be retired for users to unify preview behaviors across Defender experiences. It will still be present for admins. Clearer handling of URLs: The hover-over preview for URLs will be limited for users to reinforce that links in quarantine preview are not clickable. Simplified content loading: The "Load external content" button will be removed for some scenarios. Content will render in a secure, isolated environment. Quarantine users will experience a simplified preview interface with clearer rendering and reduced visual cues for URL interactivity: What you can do to prepare: Update any internal documentation that references the quarantine preview experience. Communicate these changes to helpdesk and support teams to reduce confusion. No configuration changes are required; the update will apply automatically. Compliance considerations: No compliance considerations identified, review as appropriate for your organization. |
| 2026-02-19 | MC Last Updated | 10/24/2025 00:50:33 | 2026-02-18T20:25:55Z |
| 2026-02-19 | MC End Time | 01/15/2026 09:00:00 | 2026-02-27T09:00:00Z |
| 2026-02-19 | MC Summary | Microsoft Defender for Office 365 is updating its quarantine email preview to enhance clarity, consistency, and security. Changes include retiring plain text view, limiting URL hover previews, and removing some "Load external content" buttons. Rollout begins November 2025, completing by mid-December, with no required user configuration. | Microsoft Defender for Office 365 is updating the quarantine email preview to simplify views, limit URL hover previews, and remove some "Load external content" buttons. Rollout starts November 2025, completing by mid-December. Users will see a clearer, more secure preview; no configuration changes are needed. |
| 2025-10-24 | MC MessageTagNames | Feature update, User impact, Admin impact | Updated message, Feature update, User impact, Admin impact |
| 2025-10-24 | MC Summary | Microsoft Defender for Office 365 will enhance the quarantine email preview by retiring plain text view, limiting URL hover previews, and removing some "Load external content" buttons. Rollout starts mid-October 2025 globally, simplifying the interface without requiring configuration changes. Update documentation and inform support teams accordingly. | Microsoft Defender for Office 365 is updating its quarantine email preview to enhance clarity, consistency, and security. Changes include retiring plain text view, limiting URL hover previews, and removing some "Load external content" buttons. Rollout begins November 2025, completing by mid-December, with no required user configuration. |
| 2025-10-24 | MC Last Updated | 10/07/2025 01:15:02 | 2025-10-24T00:50:33Z |
| 2025-10-24 | MC Messages | We're improving the email preview experience in Microsoft Defender for Office 365 to provide a clearer, more consistent, and secure workflow. These updates are designed to reduce ambiguity, simplify interactions, and reinforce security protections-helping organizations confidently use this feature as part of their protection strategy.
When this will happen: General Availability (Worldwide): Rollout will begin in mid-October 2025 and is expected to complete by early November 2025. General Availability (GCC, GCCH, and DoD): Rollout will begin in late October 2025 and is expected to complete by mid-November 2025. | Updated October 23, 2025: We have updated the timelines. Thank you for your patience.
We're improving the email preview experience in Microsoft Defender for Office 365 to provide a clearer, more consistent, and secure workflow. These updates are designed to reduce ambiguity, simplify interactions, and reinforce security protections-helping organizations confidently use this feature as part of their protection strategy. When this will happen: General Availability (Worldwide): Rollout will begin in early November 2025 (previously mid-October) and is expected to complete by mid-December 2025 (previously early November). General Availability (GCC, GCCH, and DoD): Rollout will begin in mid-November 2025 (previously late October) and is expected to complete by mid-December 2025 (previously mid-November). |
| 2025-10-24 | MC Title | Microsoft Defender for Office 365: Enhancing the quarantine email preview experience | (Updated) Microsoft Defender for Office 365: Enhancing the quarantine email preview experience |
| 2025-10-24 | MC End Time | 12/31/2025 09:00:00 | 2026-01-15T09:00:00Z |
Last updated 17 hours ago ago
