Windows 10 KB5126256 May Trigger Copilot and Crash File Explorer

A Windows 10 user says clicking files now triggers Copilot in the background and causes File Explorer to crash after installing KB5126256.

According to a Reddit report, the problem started after installing KB5126256, an ESU licensing preparation update that Microsoft says should not introduce other changes.

Copilot appears to launch in the background

The user reports that simply clicking files can trigger Copilot without any visible interaction with the assistant.

File Explorer then crashes completely, rather than only closing the folder currently in use.

Reliability Monitor initially points to Microsoft Edge as the source of the crashes, which made the problem harder to diagnose.

However, individual crash reports reportedly identify mscopilot_proxy.exe instead. The same reports list ShellEh6055x64.dll, a component associated with 4t Tray Minimizer, as the faulting module.

This suggests Copilot may be running in the background while 4t Tray Minimizer hooks into the process, creating a conflict that crashes File Explorer.

The user says 4t Tray Minimizer had worked without problems for years before the issue appeared.

KB5126256 may have exposed the conflict

The timing points to KB5126256, although the Reddit report does not establish that the update itself directly causes the crashes.

Microsoft describes the update as preparation for Windows 10 Extended Security Updates licensing, without listing broader changes that should affect File Explorer or Copilot behavior.

The report therefore raises questions about whether the update changed how Copilot components interact with third-party shell utilities.

There is no confirmed fix yet

The user did not provide a confirmed fix for the issue.

Users who experience severe problems after installing the update could consider uninstalling the affected Windows update while waiting for more information.

Microsoft has dealt with several other recent update problems. The company recently shared a temporary fix for Windows 11 black screen issues linked to KB5120998.

Microsoft also paused the KB5002907 rollout after reports that it broke Office installations.

As for Copilot, Microsoft recently announced its new Copilot Super App, expanding the assistant’s role across its software ecosystem.

Via Wccftech