Windows 10 update KB5126256 linked to File Explorer crashes

Windows 10 users have reported File Explorer crashes and unexpected Copilot activity following the installation of update KB5126256. The update is officially described by Microsoft as a preparation package for the Extended Security Updates (ESU) program, which allows users to continue receiving security patches after official support ends.

Reports indicate that selecting or opening common files can cause the File Explorer to freeze or close entirely. While initial error logs in the Windows Reliability Monitor may point to Microsoft Edge, deeper analysis of memory dumps has identified the process ‘mscopilot_proxy.exe’ as being involved.

Some technical logs also highlight a module named ‘ShellEh6055x64.dll’, which belongs to a third-party utility called 4t Tray Minimizer. This suggests a potential conflict between the third-party software and Copilot processes, though a definitive cause has not been confirmed by Microsoft.