Windows 11 users who installed the latest optional update hoping for a sleeker interface are getting a rude awakening—quite literally.
Microsoft’s latest optional preview update, KB5070311 (OS Builds 26200.7309 and 26100.7309), is causing widespread frustration among Dark Mode enthusiasts. In a cruel twist of irony, an update specifically designed to improve Dark Mode consistency has reintroduced a jarring “white flash” bug that blinds users whenever they open File Explorer.
Dubbed “Flashbang Mode” by annoyed users on Reddit and Feedback Hub, the glitch causes the File Explorer window to briefly pulse a bright white background before loading the dark theme content. For users working in low-light environments, the effect is visually painful and disruptive.
The “Flashbang” Glitch: What’s Happening?
The bug affects Windows 11 versions 24H2 and 25H2. While the operating system generally respects the system-wide Dark Mode setting, File Explorer fails to load the dark background asset immediately upon launch.
According to user reports and Microsoft’s own release notes, the white flash occurs during several common actions:
- Launching File Explorer from the taskbar.
- Opening a new tab (Ctrl + T).
- Navigating to the “Home” or “Gallery” sections.
- Toggling the “Details” pane.
This visual stutter is a regression of a similar bug that plagued Windows 10 and early versions of Windows 11, leading to the community’s weary “here we go again” reaction.
The Irony: It Was Supposed to Be Better
What makes this bug particularly stinging is the update’s original intent. KB5070311 was marketed as a “quality of life” patch that finally brought Dark Mode support to legacy dialog boxes.
For years, Windows users complained that copying, moving, or deleting files would spawn a bright white progress window even if the rest of the OS was dark. This update successfully fixes those legacy dialogs, making them dark and modern. However, by breaking the main File Explorer window in the process, Microsoft has arguably made the experience worse.
“They decided to make a ‘more consistent dark mode’… and clearly nobody at Microsoft Dev/QC uses Dark Mode ever,” wrote one frustrated user on a tech forum. Another user on Reddit joked, “I updated to protect my eyes, and now I need sunglasses to open my Documents folder.”
Microsoft’s Response & Workarounds
Microsoft has officially acknowledged the issue in the Known Issues section of the KB5070311 support document, stating:
“After installing KB5070311, you might experience issues when opening File Explorer in dark mode. The window might briefly display a blank white screen before loading files and folders.”
The company has confirmed they are working on a resolution, likely to be included in the upcoming “Patch Tuesday” security update on December 9.
Until then, users have three options:
- Live with it: Endure the flash until the next patch.
- Switch to Light Mode: A solution that defeats the purpose for most users.
- Uninstall the Update: Navigate to Settings > Windows Update > Update History > Uninstall Updates and remove KB5070311.
Other Bugs in This Update
The “flashbang” isn’t the only gremlin in this release. The same update has also been confirmed to hide the password button on the lock screen, leaving users with an invisible (but clickable) gap where the login option should be. Additionally, gamers with Intel Arc B580 GPUs have reported severe driver conflicts and black screens post-update.
Our Advice: Unless you urgently need the new AI features or specific bug fixes in KB5070311, we recommend pausing updates until Microsoft irons out these visual glitches later this month.