The latest optional Windows 11 preview update, KB5074105, is causing unexpected problems on some systems just hours after release. Early user reports point to serious webcam failures and lock screen instability, raising fresh concerns around January’s Windows update reliability.
KB5074105 targets Windows 11 versions 24H2 and 25H2 and ships as a non-security “C-update.” Microsoft lists no known issues in its official documentation, but real-world feedback tells a different story .
Laptop cameras stop working after KB5074105 install
Multiple users report that built-in laptop cameras stop functioning immediately after installing KB5074105. On affected systems, the Camera app blinks on and off repeatedly, while browsers and video meeting apps display hardware failure errors. No video or image output appears.
One report specifically mentions an Acer laptop where the webcam failed across all apps after the update. Uninstalling KB5074105 restored normal camera behavior instantly, strongly linking the issue to the update itself .
For users who rely on webcams daily for work or online meetings, the bug effectively blocks essential tasks.
Lock screen clock crashes seconds after appearing
A second issue affects the Windows 11 lock screen. Some users say the clock widget appears briefly, then crashes and disappears within seconds. Reports remain limited compared to the camera failures, but the behavior began only after KB5074105 installation.
It remains unclear whether uninstalling the update fully resolves the lock screen problem, as fewer users have tested that scenario so far.
Official guidance: pause updates and roll back drivers
A Microsoft moderator responding on the official Q&A forums acknowledged the camera issue and shared several temporary mitigation steps. These recommendations focus on stabilizing affected systems until Microsoft releases a permanent fix .
Suggested actions include:
- Run the built-in Camera troubleshooter using the Get Help app
- Update or roll back the camera driver from Device Manager
- Uninstall the camera device and restart to force driver reload
- Pause Windows Updates to prevent KB5074105 from reinstalling
Microsoft staff confirmed that uninstalling the update resolves the camera failure and advised users to pause updates if the webcam is critical for daily use.
KB5074105 is optional and safe to skip
KB5074105 is not a mandatory security patch. Microsoft distributes it as an optional preview update meant to test fixes ahead of the next Patch Tuesday. Users do not need to install it, and skipping it carries no security risk.
See also: How to Stop Windows Update Temporarily or Permanently (Windows 10 & 11)
Anyone experiencing issues can remove the update from Settings → Windows Update → Update history → Uninstall updates, or pause optional updates entirely until a revised build appears.
Another rough month for Windows 11 updates
January has already proven difficult for Windows 11 users. Earlier updates triggered boot failures on some business PCs and forced Microsoft to issue emergency out-of-band fixes for Outlook and other core components. KB5074105 now adds webcam and lock screen problems to that growing list.
For now, you may prefer to delay optional preview updates and wait for confirmed fixes before installing future builds.
Microsoft has not yet updated the Windows Release Health dashboard to acknowledge these KB5074105 issues. Users and IT admins will be watching closely for an official response or follow-up patch in the coming days.
