Windows Server 2025 memory change is crashing SQL Server and other apps
Microsoft says a memory-management change in its newest server operating system is triggering access violations and crashes in apps that use an older 32-bit memory trick.
Key points
- Microsoft has told customers that Windows Server 2025 can crash certain applications because of a recent change to how the operating system manages memory.
- The problem hits programs that use Address Windowing Extensions, an older Windows feature for reaching large amounts of memory from 32-bit software.
- SQL Server is on the affected list, especially when running with the Lock Pages in Memory policy switched on for performance.
- A permanent fix is not yet available, but Microsoft has published a temporary workaround.
- This is the third Windows Server 2025 issue Microsoft has flagged in recent months, after an update installation failure in April and a BitLocker boot loop in June.
Microsoft is warning administrators that Windows Server 2025, its newest server operating system, can crash certain business applications because of a change to the way the system hands out memory. The alert was first reported by BleepingComputer after being spotted by Microsoft MVP Susan Bradley.
The crashes hit software that relies on a feature called Address Windowing Extensions, or AWE. AWE is an old Windows trick that lets 32-bit programs, which normally cannot see more than 4GB of memory, reach much larger amounts of physical memory on the machine.
On Windows Server 2025, Microsoft changed how the underlying memory manager behaves. Programs written to expect the older behaviour can now hit errors, corrupt their own memory, or simply stop running.
Which applications are actually breaking?
The headline casualty is Microsoft SQL Server, the company's own database product, when it is configured with a Windows setting called Lock Pages in Memory (LPIM). That setting is often turned on in busy database environments so the operating system does not push SQL Server's working data out to disk.
Administrators on affected machines are seeing a familiar but ugly set of symptoms:
| Symptom | What it looks like |
|---|---|
| Access violation errors | Error code 0xC0000005 in logs |
| Memory corruption | Data in memory becomes unreliable |
| Failed maintenance jobs | DBCC CHECKDB and similar tasks fail |
| Service instability | SQL Server crash dumps, unexpected restarts |
A startup message reading "Using locked pages in the memory manager." in the error log is another signal the affected code path is in use.
Other applications that use AWE can hit the same wall. Microsoft has not published a broader list, so software vendors will need to test their own products against Windows Server 2025.
Is there a fix yet?
Not a permanent one. Microsoft says it is working on a resolution in a future Windows update and will share more when it is ready.
In the meantime, the company suggests two temporary steps. For SQL Server, administrators can disable the LPIM policy for the SQL Server service account. For other affected programs, Microsoft recommends checking whether AWE can be turned off in the application's own configuration.
Both workarounds come with a trade-off. Turning off LPIM can hurt SQL Server performance, particularly on servers under memory pressure, because Windows may start paging database memory to disk. Microsoft is telling customers to test the change in their own environment before rolling it out to production.
Should ordinary users worry?
Probably not directly. This is a server-side issue, not something that affects home PCs or Windows 11 laptops. Windows Server 2025 runs in data centres and back offices, powering business systems like databases, file shares and internal apps.
But if a company's database server crashes, the effects reach the front line quickly: slow booking systems, failed payments, appointment software that will not load. If you notice odd outages at work over the coming weeks, an AWE-related crash is one plausible cause among many.
A pattern of Server 2025 stumbles
This is the third Windows Server 2025 problem Microsoft has acknowledged in recent months. In April, the company shipped emergency updates after the KB5082063 security patch failed to install on some servers. In June, it fixed a bug that pushed some Server 2025 machines into BitLocker recovery mode, the disk-encryption safety screen that demands a recovery key, after installing an April 2026 security update.
None of the three issues involve an attacker. They are reliability problems in a young operating system. For administrators weighing when to move production workloads onto Server 2025, the pile is starting to add up.
