Windows Codex App fails to launch when Windows Null driver service is missing

Environment:

• Windows 11
• Codex CLI: 0.140.0
• Codex App: OpenAI.Codex 26.611.8604.0 from Microsoft Store
• WebView2 Runtime installed
• AppID: OpenAI.Codex_2p2nqsd0c76g0!App

Symptoms:

• Clicking Codex App did nothing
• Microsoft Store Open button did nothing
• codex app created a process but no usable window
• AppModel log showed process created then container destroyed
• Crashpad dump contained:

“Unable to open nul device needed for Node initialization.”

Diagnosis:

• cmd /d /c "echo test > nul && echo NUL_OK" failed
• Test-Path C:\Windows\System32\drivers\null.sys returned True
• sc.exe qc null returned:

[SC] OpenService FAILED 1060: The specified service does not exist as an installed service.

Fix:

• Recreated/restored the Windows Null kernel driver service
• Rebooted
• sc.exe query Null showed STATE: 4 RUNNING
• cmd /d /c "echo test > nul && echo NUL_OK" returned NUL_OK
• Codex App started successfully