codex - 💡(How to fix) Fix Codex Desktop (Windows/MSIX) v26.527.3686.0 — stuck on logo, then unusable chat UI; renderer loops on unsupported `workspace_dependencies` feature

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

26.527.3686.0 (MSIX, Microsoft Store) — OpenAI.Codex_26.527.3686.0_x64__2p2nqsd0c76g0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

The Codex Windows desktop app launches but never becomes usable. It first hangs on the logo/splash screen; if left long enough it renders the main chat UI, but the web layer is wedged — messages cannot be sent and an "Unable to send message / Loading…" modal appears that cannot be dismissed (neither OK nor × responds). The native window is not hung (IsHungAppWindow = false; it pumps OS messages), so this is a renderer / feature-flag failure rather than a crash.

Key log lines (repeat continuously):

error [electron-message-handler] Request failed error={"code":-32600,"message":"unsupported feature enablement `workspace_dependencies`: currently supported features are apps, memories, plugins, tool_search, tool_suggest, tool_call_mcp_elicitation"} method=experimentalFeature/enablement/set
error [electron-message-handler] Failed to sync experimental feature enablement hostId=local
info  [electron-message-handler] [startup][renderer] app routes mounted after <N>ms   <-- repeats (remount loop)

The backend itself is healthy: the git-origins workspace scan completes and account/read / thread/list / config/read all respond. The failure is isolated to the renderer's workspace_dependencies enablement request; at the chat level it surfaces as "Unable to send message" (cf. #20163).

Environment

What steps can reproduce the bug?

Steps

1. Launch Codex desktop (v26.527.3686.0) on Windows 11.
2. Wait through the logo screen. Either it stays on the logo indefinitely, or it renders the chat UI but typing a message and sending shows "Unable to send message / Loading…" that never resolves and cannot be dismissed.

What I tried — none fixed it:

1. MSIX Reset (Reset-AppxPackage OpenAI.Codex) — still broken.
2. Full uninstall + clean reinstall from Microsoft Store — same version redeployed, still broken (rules out corrupted local state).
3. WebView2 verified present and current (143.0.3650.96) — not the cause.
4. GPU is a modern RTX 4060 on a current (Jan 2026) driver — rules out the integrated-GPU / old-driver theory in #23624.
5. Already on the newest runtime (codex-cli 0.135.0-alpha.1); that runtime still does not list workspace_dependencies among supported features while the UI requires it. No CODEX_CLI_PATH / ELECTRON_* env var pins an older runtime.
6. No workspace_dependencies flag is stored in local .codex config or in the app's MSIX cache.
7. Window was spawning on a secondary monitor; relocating to the primary changed nothing.

Related issues: #19295, #19415, #19437, #19770, #20163, #21650, #22038, #22468, #23624

What is the expected behavior?

If the runtime does not support workspace_dependencies, the renderer should disable the feature and continue rather than remounting in an infinite loop. The app should reach a usable chat UI, and message sending should not be blocked by an unsupported experimental feature.

Additional information

This appears to be a frontend↔runtime feature-flag mismatch, likely gated server-side per account (consistent with #19295, #19437, #20163, #22468, #23624). Client-side remedies (reset, reinstall, runtime version-matching, GPU, focus/window placement) do not resolve it.