VarwoCodex Could Not Start: Identify the Failure Before Changing Setup
Separate Codex extension UI startup, authentication and task errors, and gather a useful reproduction without assuming one universal fix.
“Codex could not start” is a symptom, not a single diagnosis. First identify the surface: an IDE extension failing to draw its interface is different from the CLI failing to initialize or a model request failing after login. Begin with the official Codex IDE documentation for the relevant product. Sources reviewed October 31, 2026.
Match the failure stage
| What you see | Evidence to gather |
|---|---|
| Blank panel or UI startup message | Editor/extension version, OS and webview logs |
| Login or account error | Exact error and the product/account access involved |
| Session starts but task fails | First failing operation and its error, separately from startup |
The public openai/codex issue #56655 contains reports of a Windows/VS Code webview readiness timeout. Some reports show app-server initialization preceding the timeout. That is useful evidence about that reproduction; it is not proof of the root cause of every startup failure.
Try one reversible change at a time
Save your work, record versions and keep a copy of relevant configuration before editing it. Check current official release guidance, restart the affected editor fully and see whether the same error still occurs. Record what changed and the outcome.
An older version helping one issue reporter does not establish a universal supported fix. Do not remove authentication files, disable protections or adopt a force-install command simply because it appears in a comment.
Produce a useful bug report
Include the surface, OS, versions, exact message and a minimal sequence that reproduces it. Redact tokens, account identifiers and private file content from logs. Distinguish your own reproduction from a community workaround.
Varwo reviewed official documentation and the public issue; we have not reproduced this failure or tested a repair. For a separate agent-development workflow, see DeepSeek Harness.