Windows Desktop: turn events routed to unknown conversation ID while persisted session uses a different thread ID

Summary

ChatGPT Desktop for Windows reproducibly stops displaying responses in Work/Codex conversations.

A new conversation may successfully display the first response, but the second or subsequent turn stops displaying a response.

The Desktop logs show that the UI/session uses one thread ID, while turn/started and turn/completed notifications are received under a different ID and rejected as unknown conversation.

The corresponding persisted session transcript under ~\.codex\sessions is internally consistent and does not contain the unknown conversation ID.

Environment

• OS: Windows 11 Pro 10.0.26200 (ja-JP)
• ChatGPT Desktop package: OpenAI.Codex
• ChatGPT Desktop version: 26.908.9136.0
• Bundled Codex CLI: 0.154.0-alpha.6.2
• ChatGPT Desktop reports that it is up to date

Reproduction steps

1. Open ChatGPT Desktop on Windows.
2. Start a new Work/Codex conversation.
3. Send a simple message.
4. The first response may be displayed normally.
5. Send a second message.
6. The response is not displayed.

The issue is reproducible.

Reproduction timestamp

2026-09-15 22:49:57 JST (UTC+9)

Feedback ID

no-active-thread-01a0a564-d72f-7bf1-958f-2c252c1614af

I submitted feedback from the affected Desktop conversation with diagnostic logging enabled. The returned feedback ID had the no-active-thread- prefix.

Thread / turn ID mismatch

For the reproduction above:

UI / persisted session thread ID (A):

01a0a554-d53d-7c71-9dfb-43922ae83865

Persisted turn ID (C):

01a0a554-dca2-76a2-b459-033d19d937d5

ID reported by Desktop as an unknown conversation (B):

01a0a554-d931-7142-b0e0-c74292bdfcea

Relevant Desktop log sequence:

2026-09-15T13:49:56.677Z
Reasoning summary turn-start config resolved
conversationId=01a0a554-d53d-7c71-9dfb-43922ae83865

2026-09-15T13:49:57.151Z
Received turn/started for unknown conversation
conversationId=01a0a554-d931-7142-b0e0-c74292bdfcea

2026-09-15T13:49:57.346Z
response_routed
conversationId=01a0a554-d53d-7c71-9dfb-43922ae83865
method=turn/start
errorCode=null

2026-09-15T13:50:06.907Z
Received turn/completed for unknown conversation
conversationId=01a0a554-d931-7142-b0e0-c74292bdfcea
Persisted session transcript

The corresponding session transcript is associated with:

session/thread ID: 01a0a554-d53d-7c71-9dfb-43922ae83865
turn ID: 01a0a554-dca2-76a2-b459-033d19d937d5

Multiple event_msg records and the token_usage_record consistently use thread A / turn C.

I searched the entire corresponding session transcript for:

01a0a554-d931-7142-b0e0-c74292bdfcea

There were no matches.

Therefore, the ID reported by the Desktop renderer as an unknown conversation is neither the persisted session/thread ID nor the persisted turn ID.

Other observations

The underlying Codex/model path appears functional:

Normal Chat in ChatGPT Desktop works.
Work in ChatGPT Web works.
Standalone Codex CLI works on the same PC/account/network.
The exact Codex executable bundled with ChatGPT Desktop works when launched directly.
The persisted session transcript shows the turn completing normally under thread A / turn C.
Troubleshooting already performed
Restarted Windows
Uninstalled/reinstalled ChatGPT Desktop
Performed Windows App Reset
Confirmed ChatGPT Desktop is up to date
Tested both new and existing conversations
Regenerated the Desktop renderer/web profile
After a clean renderer profile, the first turn worked but a subsequent turn stopped again
Tested on both home Wi-Fi and company Wi-Fi
Verified DNS and TCP 443 connectivity
Verified there is no WinHTTP proxy or proxy environment variable
Temporarily removed the configured PAC URL and reproduced the same issue
Restored the PAC configuration after testing
Expected behavior

turn/started and turn/completed notifications should be associated with the active thread/conversation, and the completed response should be displayed in the Desktop UI.

Actual behavior

The persisted session completes normally under thread A / turn C, but ChatGPT Desktop receives turn/started and turn/completed associated with ID B and rejects them as unknown conversation.

The response is therefore not displayed in the Desktop UI.

Additional diagnostics

I can provide additional targeted Desktop log excerpts or session transcript fields if needed.

I would prefer not to upload complete logs or session transcripts unless necessary because they may contain local paths or conversation content.

Start with the reported Desktop log sequence and compare the active UI/persisted session thread ID with the IDs used by turn/started and turn/completed notifications. Use the supplied feedback ID and session transcript as diagnostic inputs; done means events route to the active conversation and the completed response appears in the Desktop UI.