A bug in the Windows 11 update KB5067036 allows hidden instances of Task Manager to linger in the background. This can lead to performance degradation. The issue emerged following the update released on 2025-10-28.
Impact on System Performance
The anomaly arises when Task Manager is closed using the 'x' button. This action hides but doesn't terminate the process. Repeatedly opening and closing Task Manager accumulates these hidden instances, which each consume approximately 0%–1.5% of CPU and 20–25 MB of memory. Over time, the systemic load from multiple hidden instances may degrade system performance.
Workarounds
Users can manually close these hidden Task Manager instances by right-clicking on each entry within Task Manager and selecting 'Exit'. Alternatively, executing 'taskkill /im taskmgr.exe /f' in the command prompt will terminate all active instances at once.
Possible Causes and Future Fixes
Update notes for KB5067036 hint at changes related to app grouping, suggesting this as a potential cause of the bug. Microsoft plans to address this issue in an upcoming update, which should restore Task Manager's functionality.
