Microsoft issues emergency update for Windows 11 — fixes broken March preview update rollout from last week

After rolling out an optional non-security update for Windows 11 last week, Microsoft was forced to pull it due to widespread installation issues. The cumulative update KB5079391 included several quality improvements; however, users reported that it failed to install, showing error code 0x80073712. To replace the faulty preview update, the company has now issued an out-of-band KB5086672 emergency update for affected Windows 11 25H2 and 24H2 systems.

According to Microsoft, the latest update (KB5086672) for Windows 11 “supersedes all previous updates and includes all protections and improvements from the March 2026 Windows security and non-security preview updates, as well as this installation fix.” It is available for devices running Windows 11, including those that have already installed KB5079473 or a later update. Users can also manually download the new update from the Microsoft Update Catalog.

Some key features of the optional KB5079391 update (which should now be available with the latest KB5086672 fix) include enhanced Narrator capabilities with improved image descriptions and Copilot integration. It also brings a refreshed design for account-related dialog boxes that align with Windows 11’s modern look and dark mode, as well as enhancements to File Explorer with reliable file unblocking and support for voice typing during file renaming. There are several display-related updates too, such as support for monitors with refresh rates going beyond 1000 Hz, improved auto-rotation and HDR reliability, and improved power efficiency for USB 4-connected monitors during sleep.

Microsoft has faced repeated criticism over problematic Windows 11 updates in the past, with the company promising to make changes and improve the OS. Earlier this year, the January security update KB5074109 caused widespread issues for gamers, particularly those using Nvidia GPUs. With reports of frame rate drops, visual artifacts, and instability, Nvidia itself advised users to uninstall the update as a temporary fix.

The same update also introduced a more serious issue for some users, with reports of systems failing to boot altogether. According to an AskWoody forum post, some devices encountered an “UNMOUNTABLE_BOOT_VOLUME” error after installing the security update. The affected devices ended up with a message that said “Your device ran into a problem and needs a restart. You can restart.” Additionally, some PCs refused to shut down or hibernate, and another bug resulted in Cloud-based apps, like Outlook, OneDrive, and Dropbox, not working.

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