Windows 11’s optional October 2025 update, KB5067036, has been released with an unexpected and interesting bug. Some users who installed the update reported that when they tried to close the Task Manager app, the app multiplied instead of closing.

Interesting bug in Task Manager

This bug causes unnecessary consumption of system resources and slows down computer performance. According to user reports, the problem occurs when closing Task Manager by clicking the “X” icon in the upper-right corner.

Usually, this action should close the app, but in this case, it creates a new Task Manager window. Repeating this multiple times leads to multiple instances of Task Manager running in the background, significantly increasing CPU and RAM usage.

With the KB5067036 update, Microsoft reportedly addresses an issue where some applications in Task Manager were not being mapped to their own processes. However, the release notes for the update do not mention this new multiplication bug.

In fact, Microsoft’s official documentation indicates that company officials state that they are “not currently aware of any issues with this update.” The company has yet to officially release a statement regarding this bug.

Fortunately, there are workarounds users can use to temporarily resolve this issue. Instead of using the “X” key to close Task Manager, the “End Task” button can be used.

Furthermore, users who want to close all simultaneously running instances of Task Manager can do so manually by typing the command “taskkill /im taskmgr.exe /f” in Command Prompt. It’s currently unknown when Microsoft will patch this peculiar bug.