A recent Windows 11 security update, specifically KB5058405 from May 2025, was causing some systems, mainly those running in virtual environments, to fail to start and get stuck in a recovery mode. Microsoft has acknowledged the issue and quickly released an urgent fix to resolve it.
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This problem primarily affected enterprise users running Windows 11 version 22H2 and 23H2 on virtual machines (VMs), leading to disruptive boot errors. The good news is that a non-security update is now available to prevent and fix this.
Windows 11 logo displayed on a screen
What Went Wrong?
After installing the May 2025 security update (KB5058405), affected Windows 11 PCs would encounter critical errors and fail to boot into the operating system. Users would see a recovery screen displaying error code 0xc0000098, pointing to an issue with ACPI.sys.
Think of ACPI.sys as a key driver that helps Windows manage power settings and how your computer talks to its hardware during startup. When this driver ran into a problem after the update, it essentially prevented the operating system from loading correctly, forcing the system into recovery mode.
Who Was Affected?
Microsoft confirmed that this boot failure issue was most likely to hit systems running Windows 11 22H2 and 23H2 in corporate or enterprise setups. It specifically impacted virtual machines hosted on platforms like Azure Virtual Machines, Azure Virtual Desktop, Citrix, or Hyper-V.
If you’re using Windows 11 Home or Pro on a standard desktop or laptop at home, you were generally safe from this particular problem. The issue was tied to how the update interacted with certain virtualized environments commonly used in IT departments.
The Emergency Fix Arrives
Recognizing the critical nature of an update that prevents systems from booting, Microsoft didn’t wait for the next scheduled update cycle. Over the past weekend, they released an “out-of-band” (OOB) update, meaning it’s an emergency release outside the usual schedule.
This new update, identified as KB5062170, is designed specifically to mitigate the installation and boot problems caused by the problematic May security update.
How to Get the Update
Since this is an out-of-band update, it isn’t automatically pushed through Windows Update for most users. Instead, IT administrators or affected users need to download it manually.
You can find the standalone installation package for KB5062170 on the Microsoft Update Catalog website. Just search for “KB5062170” and download the version appropriate for your system.
What If You’re Already Stuck?
If your Azure virtual machine has already installed KB5058405 and is now stuck in the recovery error loop, Microsoft recommends using Azure Virtual Machine repair commands as a workaround to get your system back online.
For those in IT environments who haven’t yet deployed the troublesome KB5058405 update but use affected virtual desktop infrastructure (VDI) on Windows 11, Microsoft’s advice is clear: skip the May security update for those systems and apply the new KB5062170 OOB update instead.
Recent Update Troubles
This incident is one of several recent challenges Microsoft has faced with Windows updates. In recent months, they’ve also had to address issues where some systems were automatically upgraded to Windows 11 despite being blocked by IT policies, problems blocking Windows 11 24H2 feature updates, and even an emergency update for Windows 10 fixing bugs that forced PCs into BitLocker recovery mode.
These repeated issues highlight the complexity of updating a global operating system and the importance of rapid responses when critical problems arise.
Wrapping Up
Getting an update that prevents your critical virtual machines from booting is certainly a stressful situation for IT teams. Thankfully, Microsoft acted quickly to provide an emergency fix with KB5062170. If you manage Windows 11 22H2/23H2 VMs, especially on platforms like Azure, Hyper-V, or Citrix, make sure to prioritize getting this new update installed to avoid or fix the boot loop issue caused by the May security patch.
For more details on the original problem and other related Windows update news, check out these articles:
- Microsoft: Windows 11 might fail to start after installing KB5058405
- Windows Server emergency update fixes Hyper-V VM freezes, restart issues
- Windows 11 KB5058411 and KB5058405 cumulative updates released
