"Applications running on Windows Server 2025 might experience access violations, memory corruption, or unexpected termination," Microsoft said in a service alert first spotted by Microsoft MVP Susan Bradley.
Microsoft's service alert and the immediate warning
Microsoft issued a service alert last week warning customers that a change in Windows Server 2025 memory management can cause some applications to crash. The company described the problem as a known issue tied to recent memory-management behavior changes in that release. Microsoft said it is working on a resolution in a future Windows update and will provide more information when it is available.
Address Windowing Extensions (AWE): what the change breaks
The problem specifically affects applications that use Address Windowing Extensions (AWE), a set of extensions that lets an application use more than 4GB of physical memory within a 32-bit virtual address space. According to Microsoft, applications relying on AWE and on memory-management behaviors present in earlier Windows Server releases can see access violations, memory corruption, or unexpected termination.
On impacted systems Microsoft listed concrete symptoms administrators may observe: memory corruption errors; access violation exceptions that can present as 0xC0000005 error codes; failures during database maintenance operations such as DBCC CHECKDB; SQL Server crash dumps; and SQL Server services stopping or restarting unexpectedly. Administrators are also seeing a startup error-log alert that reads, "Using locked pages in the memory manager."
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Get a security leadImpact on SQL Server when Lock Pages in Memory (LPIM) is enabled
Microsoft named SQL Server as one affected application when it runs with the Windows policy Lock Pages in Memory (LPIM) enabled. The advisory explains LPIM is commonly used to boost performance in scenarios where paging memory to disk is expected, and that the AWE-related memory-management change in Windows Server 2025 can interfere with that behavior. The company’s alert links the LPIM setting to the range of failures and error messages administrators are reporting on impacted systems.
Workaround: disabling LPIM and trade-offs administrators must weigh
Microsoft provided a temporary workaround rather than a permanent fix: disable the LPIM policy for the SQL Server service account. The company explicitly warned administrators to evaluate the workaround in their environments, noting that "disabling LPIM can affect SQL Server performance and memory-management behavior." For applications other than SQL Server, Microsoft advised checking whether AWE can be disabled.
Microsoft emphasized that the workaround is temporary and that a resolution will be delivered in a future Windows update. Until that update arrives, administrators must balance the operational risk of continued LPIM use against the performance consequences of disabling it.
April and June update troubles, and a resilience metric noted in the same briefing
The alert appeared alongside reminders that Windows Server 2025 has seen other recent update-related fixes. In April, Microsoft released emergency updates to address a known issue that caused the KB5082063 security update to fail to install on some Windows Server 2025 systems. In June, Microsoft fixed a separate bug that caused some Windows Server 2025 devices to boot into BitLocker recovery after installing the April 2026 security update.
Separately in the same source, the Blue Report 2026 was cited with a terse observation: "Overall prevention scores can hide what happens after initial access. Once attackers are using valid credentials, prevention drops sharply." The report is said to measure defenses technique by technique across 338 million simulations run in customer production environments.
What this means for technologists, enterprise IT, and security teams
- Technologists and security teams: Evaluate Microsoft’s workaround carefully because disabling LPIM can affect SQL Server performance and memory-management behavior; monitor error logs for the "Using locked pages in the memory manager." message and for 0xC0000005 access violation exceptions.
- Enterprise IT and database administrators: Expect to weigh immediate availability and stability against potential performance degradation if LPIM is turned off; watch for DBCC CHECKDB failures, crash dumps, and service restarts as operational signals of impact.
- Procurement and patch management leads: Factor recent April and June update fixes into test plans and rollout schedules; plan for additional testing of Windows Server 2025 updates that affect low-level memory management.
Microsoft’s advisory makes two things clear: the fault lies with a Windows Server 2025 memory-management change that broke AWE-dependent behavior, and the company has provided only a temporary workaround while it prepares a proper fix. Administrators must now choose between the short-term operational stability of disabling LPIM and the longer-term performance benefits that LPIM can deliver — a choice that Microsoft says customers should evaluate in their environments. The company’s promise of a future update answers the "when" but not yet the "how" of restoration for AWE-dependent applications.
