KB5089549 and the Missing Smooth Taskbar Auto-Hide Animation in Windows 11 - window-tip

Some Windows 11 users noticed that the smoother taskbar auto-hide animation disappeared after installing KB5089549, leaving the older and more abrupt animation in its place. The behavior can look like a regression, especially on systems where the experimental animation had previously been enabled through Windows feature rollouts or tools such as ViVeTool. However, Microsoft does not list the removal of the animation as a documented KB5089549 change, and there is no confirmed evidence that Microsoft disabled it for security reasons.

1. What KB5089549 Actually Is
2. Where the Smoother Auto-Hide Animation Came From
3. Why the Animation Can Disappear After an Update
4. Why ViVeTool May No Longer Re-Enable It
5. What the Feature Override Registry Entries Mean
6. Was the Animation Disabled for Security Reasons?
7. Possible Workarounds and Their Risks
8. Should KB5089549 Be Uninstalled?
9. Could Microsoft Bring the Animation Back?
10. What Windows 11 Users Should Take Away
11. Tags

What KB5089549 Actually Is

KB5089549 is the May 12, 2026 cumulative security update for Windows 11 versions 24H2 and 25H2. It advances Windows 11 24H2 to OS build 26100.8457 and Windows 11 25H2 to build 26200.8457.

The update combines security fixes with improvements previously delivered through optional Windows updates. Microsoft's published change log focuses on areas including Secure Boot servicing, boot reliability, connectivity, and other quality improvements.

Item	Details
Update	KB5089549
Release date	May 12, 2026
Windows 11 24H2	OS Build 26100.8457