Microsoft 365 Alert – Service Degradation – Microsoft Defender XDR – Admins may notice excessive memory usage on their Windows Server 2016 machines – NEW

Announcements Arpan Das

01/04/2026 09:22:00 AM

NHSmail Reference: INC46787846

Microsoft Reference: DZ1266872

Issue Status: OPEN

Issue Description: Admins may notice excessive memory usage on their Windows Server 2016 machines.

More info: Admins may notice delays or timeouts with third-party applications hosted on affected Windows Sever 2016 machines running Microsoft Defender for Endpoint’s Sense.

Current Update: 01/04/2026 08:50:00 AM– Following the release of Microsoft’s service optimizations to most of the affected machines, they have confirmed that the impact to the majority of machines has been remediated. They are further monitoring the health of the remainder of affected devices as their changes continue to propagate, as well as reaching a subset of affected users to provide contextual data surrounding the remaining impacted devices to determine if additional troubleshooting will be required.

Scope of impact: Any Windows Server 2016 admin may be affected.

Next update by: Wednesday, April 1, 2026, at 2:30 PM UTC