Windows: opening Codex causes sustained WMI Provider Host CPU usage and system stutter

Summary

Opening the Codex desktop app on Windows 11 causes sustained CPU usage from WMI Provider Host and Windows Management Instrumentation, even when Codex is idle and no project, workspace, or agent task has been opened.

I rely heavily on Codex for day-to-day development and university work, so this regression has a direct impact on my ability to work. Please investigate and provide a fix or workaround.

Environment

• OS: Windows 11
• App: ChatGPT powered by Codex & OWL
• Version: 26.715.31251
• Release date shown in the app: 18 July 2026
• Hardware: desktop PC

Observed behavior

1. With Codex closed, total CPU usage returns to approximately 1–10%.
2. Opening Codex without opening a project or starting an agent causes total CPU usage to rise to approximately 30–50%.
3. During the spike, Task Manager repeatedly shows roughly:

• WMI Provider Host: about 5–10%
• Windows Management Instrumentation: about 4–8%
• Microsoft Defender may also rise temporarily

1. The system intermittently stutters and the mouse can briefly stop responding.
2. Closing Codex causes WMI CPU usage to return near 0% almost immediately.
3. Reopening Codex reproduces the issue consistently.
4. ChatGPT Classic does not reproduce the issue.

Troubleshooting already performed

• Verified WMI repository:
• winmgmt /verifyrepository
• Result: WMI repository is consistent
• Tested with Codex idle and no workspace open: issue still occurs.
• Added the project folder to Microsoft Defender exclusions: no improvement.
• Confirmed no full or quick Defender scan was running.
• Stopped MSI Center services: no improvement.
• Closed other foreground applications: issue remained tied to opening Codex.
• ChatGPT Classic runs normally on the same machine.

Relevant WMI event data

The WMI Activity log contained repeated failed queries such as:

Operation = Start IWbemServices::ExecQuery - root\cimv2
SELECT __PATH, ProcessId, CSName, Caption, SessionId, ThreadCount,
WorkingSetSize, KernelModeTime, UserModeTime, ParentProcessId
FROM Win32_Process
ResultCode = 0x800706BE / 0x800706BA

Other WMI events included queries against DeviceGuard, BIOS, TPM, and processor information, but the repeated Win32_Process queries were the most prominent during the incident.

Expected behavior

Opening Codex while idle should not cause sustained WMI CPU usage, total CPU usage of 30–50%, or visible system stutter.

Additional note

This began immediately after updating to version 26.715.31251. Screenshots of Task Manager and the WMI event output are available if needed.