Codex Windows sandbox setup refresh fails; Computer Use and Node REPL unusable

Codex
,
1

Codex version: 26.818.5229.0
Windows package: OpenAI.Codex_26.818.5229.0_x64__2p2nqsd0c76g0

Problem:
Codex cannot initialize its Windows sandbox. This prevents both ordinary
sandboxed commands and Computer Use from running.

Exact errors:

  • exec_command: helper_unknown_error: setup refresh had errors
  • node_repl: windows sandbox failed: helper_unknown_error:
    setup refresh had errors
  • Node kernel exits with code 1 / stdout_eof before importing @oai/sky

Minimal reproduction:

  1. Open any local task in the Codex Windows app.
  2. Attempt a simple sandboxed command such as Get-Location.
  3. The command fails before process creation.
  4. Reset the Node REPL and execute:
    nodeRepl.write(“node-repl-alive”)
  5. The kernel exits during Windows sandbox setup.

Already attempted:

  • Restarted Codex
  • Used Windows App Repair
  • Rebuilt the Codex runtime caches
  • Fully uninstalled and reinstalled Codex

The failure persists after every attempt.

Additional checks:

  • The CodexSandboxUsers local group exists.
  • CodexSandboxOffline and CodexSandboxOnline exist and are enabled.
  • The installed Codex package reports Status: OK.
  • Elevated commands still work, but normal sandboxed commands do not.

Impact:
Computer Use is completely unavailable, so I cannot finish UI-based
application testing and evidence captures.

Please advise whether there is a sandbox-reset procedure or collect this
as a Windows Codex sandbox initialization defect.

2

Welcome to the forum!

Just answered similar in other post.

See this reply in other post.