Windows Server 2025 crashes apps over memory-management changes

Last week Microsoft sent customers a warning about a new known issue: applications on some Windows Server 2025 systems may crash because of recent changes to the memory-management subsystem.

The affected programs are those that use Address Windowing Extensions (AWE) — a set of extensions that let an application make use of more than 4 GB of physical memory within a 32-bit virtual address space. According to the company, such applications may run into access violations, memory corruption, or unexpected termination. The cause is that the new memory-management model in Windows Server 2025 differs from the behavior of earlier server OS releases, which these programs relied on. The problem was first reported by Microsoft MVP Susan Bradley, who spotted the corresponding service alert.

SQL Server at risk

Among the affected applications is SQL Server running with the Lock Pages in Memory (LPIM) policy enabled. It is typically used to boost performance in scenarios where memory is expected to be paged out to disk. On the problematic systems, users see memory-corruption errors, access-violation exceptions with code 0xC0000005, failures during database maintenance (for example, during DBCC CHECKDB), SQL Server crash dumps, as well as unexpected service stops or restarts. When the system starts, the message “Using locked pages in the memory manager” appears in the error log.

Temporary workaround

There is no permanent fix yet. As a workaround, Microsoft suggests that administrators disable the LPIM policy for the SQL Server service account, but advises weighing the consequences first: disabling LPIM can itself affect SQL Server's performance and memory behavior. For other applications, the company recommends checking whether AWE can be disabled. Work on a proper fix is under way, and it is expected in a future Windows update.

This is not the first rough edge in Windows Server 2025. In April, Microsoft released emergency updates because the security update KB5082063 would not install on some systems, and in June it fixed a bug that caused some servers to boot into the BitLocker recovery environment after the April update.

Source: Bleeping Computer