A recent Windows 11 security update has caused major disruptions for users running virtual machines, as many systems now fail to start following its installation.
According to TechSpot, the update in question—KB5058405—was rolled out automatically to Windows 11 version 23H2 and 22H2 devices. While intended to enhance system security, the patch has instead triggered critical startup failures, mainly in virtualized environments.
Affected machines stop during boot and present a recovery error message citing code 0xc0000098. In most cases, this points to a missing or corrupted system file such as ACPI.sys, which plays a key role in managing hardware power states. However, some reports suggest other essential files may also be affected.
Microsoft has acknowledged the issue and confirmed that it primarily impacts systems running virtual environments, including Azure Virtual Machines, Azure Virtual Desktop, Citrix, and Hyper-V. Devices using standard consumer editions like Windows 11 Home or Pro are unlikely to experience the same problem.
“The issue appears limited to a small number of devices in virtual machine configurations,” Microsoft said in an early statement.
Despite the company’s claim that only a small subset of users are affected, IT professionals have been vocal online, sharing troubleshooting efforts and error logs. As of now, there is no official fix.
Microsoft says it is currently investigating and urges users to report incidents via official support channels. Some IT administrators have proposed temporary workarounds like rolling back the update or using recovery tools to repair boot files, but these solutions carry risk and may not resolve the issue completely.
The situation follows previous instances where security updates introduced new complications for system stability. In environments reliant on virtual machines for critical operations, such disruptions can be especially costly.
Users and organizations managing virtual infrastructures are advised to monitor Microsoft’s support pages for future updates. Those who haven’t installed KB5058405 yet may consider delaying the patch and backing up essential data as a precaution.
Article updated 3 weeks ago. Content is written and modified by multiple authors.
