Microsoft issues out-of-band fix for Windows Server 2022 NUMA glitch

Microsoft is releasing an out-of-band patch to deal with a problem that prevented some Windows Server 2022 machines from booting.

KB5052819 is related to servers with two or more Non-Uniform Memory Access (NUMA) nodes. Affected servers failed to start up.

NUMA is a memory architecture commonly used in multiprocessing systems. In Windows Server, it is routinely used in systems with multi-core processors or physical central processing units. The technology separates memory for each processor and allows processors to access local rather than non-local memory.

NUMA is not a particularly new technology – support arrived in AMD and Intel processors in the first decade of the 21st century. Microsoft first added support to Windows Server then 64-bit versions of Windows 7, and updated Windows 10 from build 20348 to better support systems with nodes containing more than 64 processors.

The technology has found favor in enterprises and other places where high-performance computing is needed. That is assuming enterprises running Windows Server 2022 on their hardware can actually boot up the devices.

The Register contacted Microsoft to confirm when the issue was introduced and we'll update when it responds. January's security update (KB5049983) seems the most likely culprit, although it does not list problems starting Windows Server 2022 with two or more NUMA nodes as a known issue.

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KB5052819 is a non-security update, and Microsoft said: "If you installed earlier updates, only the new updates contained in this package will be downloaded and installed on your device."

It's been a busy few months for Windows Server administrators. As well as a surprise upgrade from Windows Server 2022 and 2019 to Windows Server 2025 for some unsuspecting users, some Windows Server 2025 systems with 256 or more logical processors experienced "issues."

No administrator welcomes "issues," but Microsoft released a patch to resolve the problems within weeks. The surprise upgrade was marked as mitigated by Microsoft, and it gave affected administrators the opportunity to test their backup and disaster recovery strategy.

The out-of-band NUMA patch reiterates the need to test all updates before allowing them anywhere near production, particularly when racks of computer equipment could be suddenly turned into expensive paperweights by faulty code. ®