Desktop app crashes when opening a specific thread; replacing the entire session JSONL does not resolve it

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

OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0

What subscription do you have?

ChatGPT Plus

What platform is your computer?

"$([Environment]::OSVersion | ForEach-Object VersionString) $((if ([Environment]::Is64BitOperatingSystem) {'x64'} else {'x86'}))"

What issue are you seeing?

The Codex Desktop application crashes immediately when opening one specific conversation.

The crash is 100% reproducible.

All other conversations open normally.

Environment

• Windows 11 x64
• Codex Desktop: OpenAI.Codex_26.721.4979.0_x64__2p2nqsd0c76g0
• GitHub connected

Reproduction

1. Launch Codex Desktop.
2. Open the affected conversation.
3. The application immediately exits.
4. Reopen the application.
5. Repeat.

Investigation

I spent several hours isolating the issue.

Performed tests:

• Verified the session JSONL is valid.
• Removed every input_image.
• Truncated the conversation.
• Left only session_meta.
• Removed payload.dynamic_tools.
• Compared against a healthy conversation.
• Cleared browser caches.
• Checked Windows Event Viewer.
• Checked Codex logs.
• Checked Crashpad.

Strongest reproduction

I completely replaced the contents of the problematic JSONL with a completely different conversation that opens correctly.

The ONLY thing preserved was the original thread/session ID.

The application still crashes immediately.

Changing the thread ID makes the replacement conversation open normally.

This strongly suggests the crash is associated with persistent application state indexed by the thread ID rather than the JSONL contents.

Thread ID

019f93f0-1fbb-7f52-b5a3-7086d19ee31c

Logs

No Windows crash event.

No renderer crash.

No exception.

No stack trace.

Only normal git watcher startup messages.

I can provide:

• original JSONL
• comparison report
• application logs
• cache investigation

What steps can reproduce the bug?

1. Launch Codex Desktop.

1. Open the affected conversation.

1. The application immediately exits.

1. Restart Codex Desktop.

1. Open the same conversation again.

1. The application crashes again.

The crash is 100% reproducible.

---

Investigation

I performed several isolation tests:

• Verified the session JSONL is valid.
• Removed every input_image.
• Truncated the conversation.
• Left only session_meta.
• Removed payload.dynamic_tools.
• Compared against a healthy conversation.
• Cleared browser caches.
• Checked Windows Event Viewer.
• Checked Codex logs.
• Checked Crashpad.

Strongest reproduction

I completely replaced the contents of the problematic JSONL with a completely different conversation that opens correctly.

The ONLY thing preserved was the original thread/session ID.

The application still crashes immediately.

Changing the thread ID makes the replacement conversation open normally.

This strongly suggests the crash is associated with persistent application state indexed by the thread ID rather than the JSONL contents.

Affected thread ID:

019f93f0-1fbb-7f52-b5a3-7086d19ee31c

What is the expected behavior?

The conversation should open normally.

Replacing the entire JSONL contents with a known-good conversation should eliminate the problem.

The application should not crash based solely on the thread/session ID.

Additional information

_No response_