Unexpected Reboots on Hyper-V VMs? Latest Windows Server Update Could Save You

Microsoft has released a new out-of-band update (KB5061906) to fix a critical issue that was causing certain Hyper-V virtual machines running Windows Server 2022 to freeze or reboot unexpectedly. According to the Windows release health dashboard, the problem specifically impacts Azure Confidential Virtual Machines.

Azure Confidential Virtual Machines (VMs) are a specialized offering that enhances data security by protecting information while it is being processed. Unlike traditional VMs, Azure Confidential VMs use hardware-based Trusted Execution Environments (TEEs) to encrypt data in memory. It helps to ensure that sensitive information remains inaccessible even to the cloud provider, hypervisor, or system administrators.

Azure Confidential VMs are useful for industries such as finance, healthcare, and government, where it’s critical to ensure data privacy and compliance. They support remote attestation, which allows users to verify the integrity of VMs before deploying sensitive apps. These VMs allow organizations to run their existing applications without modification.

An issue in the direct send path for a guest physical address (GPA) where confidential virtual machines running on Hyper-V with Windows Server 2022 might intermittently stop responding or restart unexpectedly, affecting service availability and requiring manual intervention,” Microsoft explained.

How to install the emergency update on Windows Server 2022?

Microsoft advises customers to install the KB5061906 patch to address Hyper-V VM freezing issues on affected Windows Server 2022 machines. This is a non-security update, which means it doesn’t address any security vulnerabilities but focuses on improving system stability or functionality.

Keep in mind that this update is only available through the Microsoft Update Catalog, and IT administrators must manually download and install it. Microsoft notes that organizations that are not experiencing VM freezing or unexpected reboots don’t need to install the KB5061906 update.

Last month, Microsoft rolled out an out-of-band update to fix a bug that was preventing Windows containers from launching on Windows Server 2025, Windows Server 2022, and Windows Server 2019 machines. This issue primarily affected containers running under Hyper-V isolation mode.