Windows 11 Task Manager Bug: What’s Happening, Why It Matters, and How to Fix It
A new bug affecting Windows 11’s Task Manager has been discovered following the October 2025 Preview Update (KB5067036). The issue causes multiple background instances of Task Manager to remain active even after closing the app, leading to increased memory use and system slowdown over time. While not critical for most users, this glitch can cause noticeable performance degradation on systems where Task Manager is frequently opened and closed throughout the day.
Below is a comprehensive breakdown of what’s happening, how to identify the issue, temporary fixes, and steps to avoid it until Microsoft releases an official patch in November.
🧠 Understanding the Bug
After installing Windows 11 update KB5067036, users have reported that Task Manager fails to close properly when exited using the standard window controls (the “X” button).
When reopened, a new process instance (taskmgr.exe) launches without the previous one terminating. Over time, this results in several hidden instances of Task Manager continuing to run in the background simultaneously.
Each instance consumes system resources — particularly RAM and CPU cycles — which can accumulate if the app is opened multiple times in a session. On modern PCs with 8GB or more of RAM, the impact may be minor initially, but on laptops and mid-range systems, the unnecessary background load can become significant.
⚙️ What Causes It
The problem stems from a process handle leak in the Task Manager process termination routine introduced in KB5067036, a cumulative preview update.
Specifically:
- When a user closes Task Manager via the top-right “X,” the process remains active due to improper release of background threads.
- Each subsequent launch spawns a fresh instance instead of connecting to the existing process.
- Windows does not automatically terminate orphaned Task Manager processes because it interprets them as active sessions.
Microsoft has acknowledged the issue through Windows Feedback Hub reports, and it is currently under review. A permanent fix is expected in the November 2025 Patch Tuesday update.
🔍 How to Check if You’re Affected
- Open Task Manager (Ctrl + Shift + Esc).
- Go to the Details tab.
- Scroll down and look for multiple entries of taskmgr.exe.
If you see two or more instances, your system is affected. Each instance will likely show minimal CPU use but noticeable memory allocation (typically 20–50 MB per instance).
You can also use Command Prompt to confirm:
tasklist | find "taskmgr.exe"
This command will list all running Task Manager processes.
🛠️ Temporary Fixes
Until Microsoft resolves the issue, there are two effective ways to stop all background Task Manager instances.
Option 1: End Tasks Manually
- Open Task Manager → Go to the Processes or Details tab.
- Find all instances of Task Manager (taskmgr.exe).
- Right-click each one and select End Task.
This method works but can be tedious if many instances are running.
Option 2: Use Command Prompt or PowerShell
For a faster and cleaner fix:
- Open Command Prompt as Administrator.
- Run the following command:
taskkill /im taskmgr.exe /fThis instantly terminates all Task Manager processes currently running. - Wait a few seconds, then reopen Task Manager if needed.
Alternatively, PowerShell users can run:
Stop-Process -Name taskmgr -Force
🚫 How to Avoid the Bug
Until the official patch arrives, here are the best ways to prevent Task Manager duplication:
- Avoid closing Task Manager using the “X” button.
- Instead, locate Task Manager under Background Processes in the app itself.
- Right-click and select End task to close it completely.
- Use keyboard shortcuts to reduce repeated launches.
- Pin Task Manager to the taskbar or start menu to avoid frequent reopening.
- Restart your PC regularly.
- This ensures all ghost instances are cleared from memory.
- Consider uninstalling the KB5067036 Preview Update.
- If the issue severely affects performance, you can remove the preview build:
- Open Settings → Windows Update → Update history → Uninstall updates.
- Select KB5067036 and choose Uninstall.
- Restart your device.
- Note: This will revert your system to the September stable build, which does not contain the bug.
- If the issue severely affects performance, you can remove the preview build:
🧩 Impact on System Performance
For most users, the effect will be mild — typically a few hundred MB of extra memory usage. However, power users, developers, or IT professionals who open Task Manager repeatedly may experience:
- Gradual memory bloat, especially on lower-RAM systems.
- Reduced responsiveness when launching new apps.
- Slightly longer boot times after multiple restarts if the processes remain orphaned.
To check resource impact, you can monitor memory usage in Resource Monitor (resmon.exe) under the Memory tab.
🗓️ What’s Next from Microsoft
Microsoft is expected to release a fix on November 11, 2025, as part of the regular Patch Tuesday update cycle. Insiders may receive an early fix through Dev Channel builds before that date.
Once the patch is deployed:
- Task Manager will correctly release its process handles upon closing.
- Future instances will not duplicate or consume excess system memory.
Users can track update progress through:
- Windows Feedback Hub → Known Issues → Task Manager Duplication
- Microsoft Support KB Page for KB5067036
✅ Summary: Quick Reference
| Step | Action | Command or Path |
|---|---|---|
| Identify bug | Check multiple Task Manager processes | `tasklist |
| Fix | End all instances | taskkill /im taskmgr.exe /f |
| Avoid issue | Close from inside Task Manager | Background Processes → End Task |
| Roll back update | Uninstall KB5067036 | Settings → Windows Update → Uninstall updates |
| Patch ETA | November 11, 2025 | Automatic via Windows Update |
Final Thoughts
While the Task Manager duplication bug is not catastrophic, it’s a good reminder to stay cautious with optional preview updates. These releases are meant for early testers and may contain issues that will be resolved in the next stable build.
If you rely heavily on Task Manager for system monitoring, apply the temporary fixes above and avoid repeatedly reopening it. Once the November update arrives, it’s expected that Microsoft will fully resolve the issue — restoring normal Task Manager behavior for all Windows 11 users.
