SHD / MC Checker

[investigating] DZ1163645 | Microsoft Defender XDR | Some macOS devices with multiple security providers may have no display output



DZ1163645 | Microsoft Defender XDR | Some macOS devices with multiple security providers may have no display output

Status investigating
Classification advisory
User Impact MacOS devices with multiple security providers may have no display output.
Last Updated 10/01/2025 21:39:23
Start Time 09/29/2025 20:00:00
End Time
Latest Message Title: Some macOS devices with multiple security providers may have no display output

User impact: MacOS devices with multiple security providers may have no display output.

More info: This issue is not specific to a single macOS device version and could affect users of any version of macOS.

Current status: Further analysis indicates that the root cause is a deadlock in Apple enterprise security framework when multiple security providers are listening to events, and we’ve updated the “root cause” section of communications to reflect this. During the rollout of our performance update between Defender on macOS and the Apple enterprise security framework, we isolated the deadlock and updated the configuration for Microsoft Defender for Endpoint on macOS devices to avoid the offending security deadlock. We’re monitoring service health telemetry to confirm the issue is resolved after correcting the configuration.

Scope of impact: Some users may see black screen crashes for macOS devices if their macOS devices were updated after September 29, 2025.

Start time: Monday, September 29, 2025, at 8:00 PM UTC

Root cause: A deadlock in Apple enterprise security framework occurs when multiple security providers are listening to events.

Next update by: Thursday, October 2, 2025, at 3:00 AM UTC