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[Windows] Computer Use fails with spawn EPERM after Codex update #37272

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[Windows] Computer Use fails with spawn EPERM after Codex update#37272
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appIssues related to the Codex desktop appbugSomething isn't workingcomputer-usewindows-osIssues related to Codex on Windows systems

Description

@gutogral-tech
gutogral-tech
opened on Aug 6, 2026

Summary

Computer Use worked on Codex app version 26.727.6591.0, but after the Microsoft Store updated the app to 26.730.8199.0, every Computer Use action fails immediately with spawn EPERM, before windows can be enumerated or any application can be controlled.

The failure reproduces both in an existing task and in a newly created Work task.

Environment

  • Windows 10 Enterprise 22H2 (build 19045.6456)
  • Codex app: 26.730.8199.0
  • Computer Use plugin/runtime: 26.730.61639
  • Same result when Codex is started normally or elevated

Steps to reproduce

  1. Install and enable the Computer Use plugin and skill.
  2. Click Try now or create a new Work task.
  3. Ask Computer Use to inspect the visible desktop/RDP window or launch an allowed Windows application.
  4. The first controller action fails immediately.

Examples that fail:

  • sky.list_windows()
  • sky.launch_app({ app: "winword.exe" })

Actual behavior

The local Computer Use controller returns spawn EPERM before listing windows. No mouse, keyboard, application, or RDP interaction occurs.

Expected behavior

Computer Use should enumerate visible windows and control an allowed Windows application, as it did before the app update.

Troubleshooting already performed

  • Repaired the Codex app through Windows Settings.
  • Uninstalled and reinstalled the Computer Use plugin.
  • Restarted Codex and reproduced in a new task.
  • Regenerated the bundled cua_node runtime from scratch.
  • Verified that the bundled controller executable exists and has Read/Execute permission.
  • Verified that the native controller pipe is created.
  • Tested both normal and elevated Codex processes.
  • Checked Microsoft Defender, AppLocker, and Code Integrity logs; no corresponding block or quarantine event was found.

The issue began immediately after the automatic Codex update, so this appears to be a regression or a version mismatch between Codex 26.730.8199.0 and the Computer Use runtime 26.730.61639.

Activity

  1. github-actions
    added
    bugSomething isn't working
    appIssues related to the Codex desktop app
    windows-osIssues related to Codex on Windows systems
    computer-use
    on Aug 6, 2026

  2. github-actions commented on Aug 6, 2026

    @github-actions
    github-actionsBot
    on Aug 6, 2026 – with GitHub Actions
    Contributor

    Potential duplicates detected. Please review them and close your issue if it is a duplicate.

    Powered by Codex Action

  3. despondent9 commented on Aug 6, 2026

    @despondent9
    despondent9
    on Aug 6, 2026

    Confirming the same regression on another Windows system.

    • Codex desktop app: 26.730.8199.0
    • Computer Use plugin/runtime: 26.730.61639
    • Platform: Microsoft Windows NT 10.0.26200 x64, version 25H2, build 26200.8875
    • sky.list_apps() and sky.list_windows() both return spawn EPERM
    • Node spawnSync("C:\\Windows\\System32\\where.exe", ["cmd.exe"]) also returns EPERM
    • The failure occurs before any mouse movement, window enumeration, or Excel interaction
    • Computer Use, Any App, and Microsoft Excel permissions are enabled
    • Repairing the app, restarting Windows, using the unelevated sandbox, and disabling the private desktop did not help
    • Uploaded thread: 019fd74d-9b61-7a70-935e-6a2aed1d43db
    • Screenshots and the full reproduction report are available in [Windows Desktop] Computer Use fails to launch because child processes return spawn EPERM #37284

    This appears to be the same regression. I will close #37284 as a duplicate so the evidence can be consolidated here.

  4. Rowdster commented on Aug 12, 2026

    @Rowdster
    Rowdster
    on Aug 12, 2026

    I got codex to fix this. I happened to be running elevated and yolo, terra medium.

    My prompt:
    You are running with elevated permissions but still have your windows store sandbox limitations. Can you fix this issue of you not being able to use ultracode?

    Codex response:

    Fixed and verified.
Ultracode was resolving codex to an npm shim, which Windows Node cannot spawn (EPERM). I updated its Windows resolver in [ultracode-engine.js](C:\\Users\\Admin.codex\\plugins\\cache\\just-every\\ultracode\\0.3.0+codex.20260601143116\\scripts\\ultracode-engine.js) to automatically use Codex’s launchable local CLI binary instead of the Store-protected one.
Verification passed:
One real worker returned worker launched.
Two workers launched concurrently and returned A and B.
No spawn EPERM errors.
Note: this patch is in the installed plugin cache; a future Ultracode plugin upgrade may replace it until the upstream plugin incorporates the resolver change.
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