Image: Microsoft
Summary created by Smart Answers AI
In summary:
- PCWorld reports that Windows 11’s mandatory January security update KB5074109 is causing widespread system problems including black screens and application crashes.
- The update affects critical functions like File Explorer, shutdown/sleep modes, and causes the classic Outlook app to malfunction consistently.
- While Microsoft has resolved some issues, others persist with potential fixes expected in February’s update cycle.
Microsoft has really stepped in it with the first Windows 11 update of 2026. Reports from annoyed Windows users are cropping up regarding various errors caused by the KB5074109 update.
According to said reports, Windows 11 PCs that installed the KB5074109 update on Microsoft’s Patch Tuesday for January 2026 are experiencing black screens (formerly known as blue screens). Furthermore, the classic Outlook app is crashing for some and File Explorer is ignoring settings stored in the desktop.ini file.
In addition, some computers can no longer be shut down and sleep mode is broken for some. (There’s also a thread about this on Reddit.) Some third-party apps, like Citrix Director, also no longer work.
Microsoft has already solved—or at least confirmed—some of these problems: shutdown (solved), remote desktop connections (solved), and classic Outlook (not yet solved).
The KB5074109 update is a mandatory update that addresses security vulnerabilities. Every Windows 11 PC installs it automatically. Windows Latest asked Microsoft for a statement about these issues, but Microsoft only said that it currently has nothing further to say.
That said, Windows Latest noted that Microsoft had marked some of the newly discovered (but as yet unconfirmed) issues with a “looking into it” label in the Feedback Hub, such as the one with File Explorer and desktop.ini. Microsoft may release the corresponding repair patches on the next Patch Tuesday, which will be on February 10th, 2026.
This article originally appeared on our sister publication PC-WELT and was translated and localized from German.
Author: Hans-Christian Dirscherl, Managing Editor, PC-WELT
Hans-Christian Dirscherl began his IT life with Autoexec.bat and config.sys, Turbo-Pascal and C, Sinix and Wordperfect. He has been writing on almost all IT topics for around 25 years, covering everything from news to reviews and buying guides.
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