Windows desktop app can be running with no visible window until AppX relaunch #17818

What version of the Codex App are you using (From About Codex)?

26.409.1734.0

What platform is your computer?

Microsoft Windows 11 Pro x64 (reported by Get-ComputerInfo as OsBuildNumber 26200)

What issue are you seeing?

The packaged Windows desktop app can be running with multiple Codex.exe processes but no visible Codex window. From the user's perspective, Codex looks closed even though the packaged app is already alive in the background.
This was not a CLI issue. It was the Microsoft Store packaged app at:
C:\Program Files\WindowsApps\OpenAI.Codex_26.409.1734.0_x64__2p2nqsd0c76g0\app\Codex.exe

What steps can reproduce the bug?

I do not yet have a deterministic repro from a cold launch every time. What I observed today was:

1. User asked me to check whether Codex was open.
2. Process probe showed several packaged Codex.exe processes already running.
3. Window probe using Win32 EnumWindows + IsWindowVisible found no visible packaged Codex window.
4. A clean relaunch of the packaged app restored a visible window immediately.
   The relaunch that recovered the UI was:
   powershell Get-Process | Where-Object { .Path -like 'C:\Program Files\WindowsApps\OpenAI.Codex_*\app\Codex.exe' } | Stop-Process -Force Start-Process explorer.exe 'shell:AppsFolder\OpenAI.Codex_2p2nqsd0c76g0!App'

What is the expected behavior?

If the packaged app is running, the user should have a visible/focusable Codex window, or the app should restore the existing window when launched again.

Additional information

Current evidence from this session:

• Initial probe showed packaged Codex.exe processes with no visible packaged Codex window.
• The first visible-window search also found an unrelated MT5 window titled Modular_EA_Codex, so title-only detection would have been misleading. I had to verify by process path instead.
• After the clean relaunch, a visible packaged Codex window appeared with title Codex.
• I then ran a bounded control repro:
  • T+0s: 0 packaged Codex processes, 0 visible packaged Codex windows
  • T+8s after AppX launch: 5 packaged Codex processes, 1 visible packaged Codex window
  • T+68s: still 5 packaged Codex processes, still 1 visible packaged Codex window
    So the strongest report here is not "it always crashes on startup". It is specifically: there are cases where the packaged app is already running but has no visible UI until a clean AppX relaunch.
    If useful, I can gather follow-up evidence next time this happens again, such as AppModel events and any app-local logs around the invisible-window state.