A bug in Windows 11 has been causing disruptions, particularly affecting the Explorer.exe process, leading to the desktop user interface and taskbar disappearing for users. Microsoft has acknowledged the issue and will release a fix in the optional update, Windows 11 KB5074105, in January 2026. The problem affects Windows installations with certain startup applications configured, causing Explorer.exe to stop responding upon signing in. Users are advised to manually restart Explorer.exe via Task Manager if it becomes unresponsive. The KB5074105 update will also fix issues with Explorer not displaying custom folder names correctly and resolve problems with an unresponsive lock screen and black screens linked to a previous update.