Windows 10 update triggers Copilot background launch and File Explorer crashes
Clicking a file in Windows 10 now comes with a risk. After installing update KB5126256, some users find Copilot launching in the background. File Explorer doesn't just close a folder. It shuts down completely. Users lose access to their files in an instant.
KB5126256 was first released on September 8, 2026, and is automatically delivered via Windows Update to devices running Windows 10 version 22H2 with patches from October 14, 2025 or later.
Microsoft calls KB5126256 a licensing prep package for Extended Security Updates (ESU) on Windows 10 version 22H2. The official Microsoft documentation says this update does not activate ESU or add new fixes. It is not a feature update.
But the timing is clear. Users say the crashes started right after installing KB5126256. At first, Reliability Monitor blamed Microsoft Edge. This made it harder to find the real cause. Later, deeper checks showed Copilot was involved. Technical posts on Windows forums show the crash logs always mention both Copilot and the 4t Tray Minimizer module. The problem is specific. These two do not play well together.
Independent technical reviews have found that Reliability Monitor initially misattributed the crash to Microsoft Edge, but subsequent analysis identified Copilot as the actual process involved. This misdiagnosis points to limitations in Windows' error reporting rather than direct evidence of Edge being at fault.
Microsoft has been pushing Copilot further, with a new Copilot Super App planned to tie the assistant deeper into its ecosystem. But this bug shows the risk of background changes. Updates can break things, especially when third-party tools are in the mix. Until Microsoft fixes the conflict, users who rely on shell extensions like 4t Tray Minimizer face a tough choice. Security updates or a stable desktop? They can't have both right now.
Spanish and Turkish tech sites have covered the issue. Microsoft still has not recognized the bug or offered a fix. Reports stress that KB5126256 "should not" make changes beyond ESU prep. But with no word from Microsoft, users have no clear path forward.
