Microsoft 365 Alert – Service Degradation – Microsoft Defender XDR – Admins may have experienced delayed security alerts in MDI – RESOLVED

03/12/2025 08:44:00 AM

NHSmail Reference: INC46696297

Microsoft Reference: DZ1191513

Issue Status: RESOLVED

Issue Description: All admins may have experienced delayed security alerts in Microsoft Defender for Identity (MDI).

Current Update: 03/12/2025 08:48:00 AM – Microsoft have identified that a recent update to the MDI service inadvertently introduced a code regression that led to downtime in alert forwarding. They have deployed a hotfix to mitigate impact and have confirmed, following a period of monitoring service telemetry, that the issue is resolved.

Scope of impact: Your organization was affected by this event, and all admins attempting to access security alerts in MDI may have been impacted.

Root cause: An update to the MDI service inadvertently introduced a code regression that led to downtime in alert forwarding, resulting in impact

Next Steps: Microsoft are reviewing their update procedures to better identify similar issues during our development and testing cycles.