[Windows][26.825.6671.0] IMPORTANT FATAL ISSUE: Mid-session cross-task failure cascade: missing tool outputs, duplicate ordinals, and MoAppHang

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

26.825.6671.0

What subscription do you have?

Pro

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

This report concerns a recurring mid-session failure cascade, not a startup failure. Codex Desktop launches and initially works normally.

During active tool-running tasks, I repeatedly observe several of the following symptoms together:

1. A command/tool appears to complete, but its output is not persisted or attached to the task.
2. The affected turn remains inProgress, becomes interrupted, or loses part of its visible history.
3. Thread-history projection reports a duplicate or regressed ordinal.
4. The desktop app-server/UI restarts, reloads, or becomes unresponsive.
5. Unrelated tasks—including newly created tasks—are interrupted at approximately the same time.
6. The app eventually displays “ChatGPT hit a snag.”
7. Windows records Event ID 1002 / MoAppHang with HangType Top level window is idle.

Exact projection errors observed in two independent tasks:

thread history projection ... expected ordinal 312, got 311

thread history projection ... expected ordinal 132, got 131

The second error occurred in a newly created XHigh task. This has reproduced with no Ultra tasks or Ultra subagents running, so it does not appear to be specific to Ultra reasoning, extremely long conversations, or one previously corrupted task.

Other observed symptoms include:

• Custom tool call output is missing for call id ...
• Turns remaining indefinitely inProgress
• Turns becoming interrupted after an app-server/UI restart
• Completed work disappearing when a task is reopened
• One affected task apparently destabilizing other independent tasks
• The entire desktop window becoming unresponsive

Windows Event Viewer records:

Event ID: 1002
Event name: MoAppHang
HangType: Top level window is idle

I cannot yet prove whether the ordinal mismatch causes the app-server restart, whether the restart creates incomplete history, or whether both are consequences of another failure. I am reporting them together because they repeatedly occur as parts of the same observable failure sequence.

What steps can reproduce the bug?

Feedback ID: 01a051a8-4865-7ae3-a6fa-24f8396454d4

What is the expected behavior?

No response

Additional information

This is a very bad bug that is impacting many POWER users that are doing over 2b tokens daily.

Troubleshooting already attempted

• Restarted Codex and Windows
• Used Windows Repair/Reset
• Uninstalled and reinstalled the Microsoft Store app
• Confirmed that the newest Store package was installed
• Reduced the number of simultaneous tasks
• Stopped using Ultra reasoning
• Stopped using Ultra subagents
• Tested with brand-new XHigh tasks

The issue still recurred.

Cross-version recurrence

Windows has recorded the same MoAppHang / Top level window is idle signature across multiple Codex Desktop versions:

App version	Observed occurrences
26.825.6671.0	Five hangs on August 30
26.825.5331.0	August 29
26.825.4187.0	August 29
26.818.x	August 22–23
26.810.x	August 16

I cannot confirm that every historical hang had the same internal cause, but this demonstrates that reinstalling and changing reasoning levels have not eliminated the Windows failure.

Related reports and distinction

Existing reports appear to document individual portions of this failure cascade:

• #40630 — mid-session engine exit followed by expected ordinal N, got N-1, missing outputs, and damaged tasks
• #41079 — duplicate ordinal causing the history projection to stop
• #41566 — duplicate ordinal following an unfinished turn
• #41236 — Windows app-server restarts during tool calls and loses completed outputs
• #41333 — Windows crash followed by a stuck inProgress turn and ordinal mismatch
• #41581 — Windows desktop closes during long/tool-heavy sessions
• #41591 and #41475 — orphaned turns hide later durable history
• #41551 and #41571 — the same MoAppHang signature, but during startup before the UI becomes usable
• #35746 — a possibly related implementation-level record-skipping and ordinal-reuse mechanism

This report does not claim that every linked issue has one root cause. Its distinct evidence is that missing tool outputs, duplicate ordinals, stuck turns, cross-task app-server/UI interruption, and Windows MoAppHang can occur together on the newer 26.825.6671.0 build, including in brand-new XHigh tasks.

Diagnostic material available

I can provide the following privately or after redaction:

• In-app feedback/session IDs
• Sanitized log excerpts surrounding both ordinal errors
• Affected task/session IDs
• Windows Event Viewer XML and report IDs
• Timestamps correlating missing tool outputs, app-server restarts, and MoAppHang

I have not uploaded raw rollout files, process dumps, or unredacted logs because they may contain prompts, local paths, task contents, or other private information.

Start by comparing the linked reports, especially #40630, #41079, #41236, and #41333, with the supplied feedback ID and sanitized logs. Correlate ordinal errors, missing outputs, app-server restarts, and Windows Event ID 1002; done means establishing a reproducible failure sequence and documenting whether these symptoms share a cause or require separate fixes.