Microsoft has rolled out an emergency hotfix aimed at resolving a critical issue affecting Hyper-V virtual machines on Windows Server 2022, which were freezing or restarting unexpectedly. This issue is primarily affecting Azure confidential VMs, designed to ensure data security during processing. The underlying problem relates to how the system manages memory paths using guest physical addresses (GPA), leading to possible VM lock-ups or random reboots, ultimately impacting uptime and necessitating manual fixes.
To address the situation, the update, designated as KB5061906, was released as an out-of-band patch, intended to replace earlier fixes while targeting specific issues within the Hyper-V direct send path. Microsoft clarifies that this update is especially crucial for Azure confidential VMs and typically won’t impact standard Hyper-V installations unless users are operating on preview versions or test environments.
It’s important to note that the fix does not appear automatically through Windows Update. Affected users will need to manually download and install the standalone MSU package from the Microsoft Update Catalog. Microsoft also recommends that if you have not applied the May 2025 Patch Tuesday update (KB5058385) and your Hyper-V setup operates on Windows Server 2022, then you should install KB5061906. If your setup is unaffected, this update can be skipped.
This incident is not the first for Hyper-V, as Microsoft has previously issued several emergency patches within the last two years to mitigate issues like broken container launches, boot failures, and VM startup problems in both Windows Server 2019 and 2022.
For more details, refer to Microsoft’s support articles: