Microsoft has released the KB5070311 non-security preview update for Windows 11, offering enhanced support for dark mode enthusiasts. However, this update introduces an issue with File Explorer's dark mode, causing parts of the app to occasionally flash. The problem results in the application window briefly displaying a blank white screen before loading files and folders. Actions that can trigger this include launching or switching from the Home and Gallery sections, opening new tabs, toggling the Details pane visibility, and requesting additional information during file copy operations. While this is not a critical security issue, it may produce inconvenience to users accustomed to dark mode.

Although Microsoft hasn't yet resolved this issue and has listed it in the "known issues" section, we've managed to recreate what the bug looks like before it returns to normal. It usually lasts for only a second, but it's enough to be annoying, especially if you're using dark mode. The company is working on a fix, which will be included in a future non-security update package. So, those who prefer dark mode will need to endure the inconvenience of flashing white squares a bit longer. It also raises questions about what causes this behavior within File Explorer. With recent issues that Microsoft is actively addressing, it might be due to conflicts between Win32 UI elements and modern WinUI/XAML overlays.