Microsoft's latest updates for Windows 11 present a mixed bag for users, combining the rollout of a problematic optional update with a significant policy change for a key security feature. While the optional KB5070311 update is causing visual glitches and installation headaches for some, a separate development sees Microsoft removing a major barrier to accessing the "Smart App Control" security tool, making it more widely available. This dual narrative highlights the ongoing balancing act between introducing new features, maintaining security, and ensuring system stability.
The Troublesome Optional Update KB5070311
The optional cumulative update KB5070311, released on December 1st for Windows 11 versions 24H2 and 25H2, is intended to deliver functionality, performance, and reliability improvements. However, its deployment has been marred by several confirmed issues that are impacting user experience. Microsoft's own support documentation acknowledges that the update can cause File Explorer to briefly display a blank white screen when opened in dark mode before loading files and folders. Independent reports suggest the problem may be more pervasive, with white flashes occurring when switching between pages within File Explorer regardless of the starting view.
Update Details at a Glance:
| Update / Feature | Key Change / Issue | Impact |
|---|---|---|
| KB5070311 (Optional) | Causes visual glitches in File Explorer dark mode; may fail to install (error 0x80070306). | Negative - Wait for a fix if affected. |
| Smart App Control (SAC) | Clean-install requirement removed. Can now be toggled on/off in settings on any Windows 11 install. | Positive - Enables stronger security for all users. |
Installation Hurdles and Additional Glitches
Beyond the dark mode visual bugs, users are encountering other obstacles with KB5070311. The update has been reported to fail installation for some, generating error codes such as 0x80070306. For those who successfully install it, there are concerns about potential conflicts with Intel Arc GPU drivers. Another, albeit more niche, issue affects the Windows Hello login interface. In certain managed enterprise environments, the password icon can become invisible when selecting "Sign-in options," though the functional button behind it remains. Microsoft notes this issue primarily affects enterprise setups and is less likely to occur on personal Windows Home or Pro devices.
Microsoft Relaxes "Smart App Control" Installation Requirement
In a positive and separate development, Microsoft has quietly removed a major restriction for one of Windows 11's exclusive security features. "Smart App Control" (SAC), a cloud-based service that proactively blocks untrusted or potentially harmful applications from running, previously had a stringent requirement: it could only be enabled on a clean, fresh installation of Windows 11. This meant users who upgraded from an older version of Windows were locked out of using the feature. This policy has now been reversed.
Affected Systems & User Guidance:
- KB5070311 Issues: Primarily affects Windows 11 versions 24H2 and 25H2. Enterprise users are more likely to encounter the invisible password icon bug.
- SAC Availability: The feature is exclusive to Windows 11. The policy change is confirmed in builds for Dev and Beta channels, with a wider rollout expected.
- Actionable Steps: Users should avoid the optional KB5070311 if dark mode stability is critical. All users can now check for SAC in Windows Security > App & browser control > Smart App Control settings.
Universal Access to Enhanced Security
With updates like KB5070311 for Dev and Beta channels, Microsoft has confirmed the removal of the clean-install mandate for SAC. Users can now enable or disable the feature at any time through Windows Security settings, regardless of whether their system was set up via a clean install or an in-place upgrade. Microsoft advocates for SAC as a superior layer of defense because it blocks threats before they execute, reducing system load compared to traditional anti-malware that scans active processes. The company suggests this pre-execution blocking can be particularly beneficial for performance on lower-specification PCs.
Navigating the Current Windows 11 Update Landscape
The current situation presents a clear path for users. For those considering the optional KB5070311 update, caution is advised. It may be prudent to wait for Microsoft to issue a fix for the known dark mode and installation issues before proceeding, especially for users who rely on a stable File Explorer experience or use Intel Arc graphics. Conversely, the change to Smart App Control policy is an unambiguously good update that broadens access to a robust security tool. Users running Windows 11, particularly on older hardware where performance is a concern, should check their Windows Security settings to explore enabling SAC, as it now offers potent protection without any special installation hurdles.