Microsoft's Windows K2 Overhaul Targets Performance Fixes for Windows 11
Microsoft is finally addressing long-standing issues with Windows 11's performance. The company has confirmed that it's working on major speed fixes for File Explorer, Start menu, and taskbar lag, which have plagued users since the OS launched in 2021.
The overhaul, part of Microsoft's broader internal quality initiative dubbed 'Windows K2', aims to migrate legacy UI components to modern frameworks like WinUI and improve performance consistency across core shell surfaces.
Design and Research lead Marcus Ash has confirmed that these improvements are being pushed to all Windows 11 users, with a broader rollout tied to the 26H2 update this fall. Some fixes have already shipped, including an optional preview update KB5120998 released August 27, which speeds up File Explorer's Home page in production builds.
Users on 25H2 will receive many of these changes through cumulative updates before 26H2 arrives, so keeping Windows Update active is the most direct path to a faster system. The comprehensive package of Start, Taskbar, Search, and File Explorer improvements is expected to land broadly with the 26H2 update this fall.