Desktop Codex cannot open older chat sessions after recent update

[alyakishevdmitriy-pixel]

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

Version 26.601.20914 • Released 2 июн. 2026 г.

What subscription do you have?

Plus

What platform is your computer?

Windows 11

What issue are you seeing?

Title: Desktop Codex cannot open older chat sessions after recent update

Environment:

• OS: Windows 11
• Codex Desktop
• Problem started immediately after the latest update

Description:

After updating Codex Desktop, newly created chats work normally.

However, older chat sessions no longer open correctly. When attempting to open previous conversations, Codex eventually reports:

"Most recent error: memory allocation of 2862678 bytes failed"

Observations:

• New chats work correctly.
• Existing session files are still present in ~/.codex/sessions.
• session_index.jsonl exists and is not corrupted.
• session_index.jsonl size: 1974 bytes.
• session count in sessions folder: 25.
• Largest session files are approximately 1–2 MB.
• Config file appears normal.
• Multiple Codex processes remain running after launch.
• Problem began only after the latest update.

Expected behavior:

Older chat sessions should open normally.

Actual behavior:

Opening older chats results in failure and memory allocation errors while new chats continue to function.

Additional information:

The issue appears related to reading or migrating older session data after the update rather than missing or corrupted session files.

What steps can reproduce the bug?

1. Open Codex Desktop on Windows 11.
2. Confirm that new chats can be created and opened normally.
3. Try to open an older chat session created before the latest Codex update.
4. The chat content does not load correctly.
5. Codex eventually shows the error:

Most recent error: memory allocation of 2862678 bytes failed

Additional diagnostics:

• ~/.codex/sessions exists and contains 25 items.
• ~/.codex/session_index.jsonl exists.
• session_index.jsonl size is 1974 bytes.
• session_index.jsonl contains 14 lines.
• Largest session files are only around 1–2 MB.
• New chats work correctly.
• The issue started immediately after the latest Codex update.

I do not have a minimal code snippet because this appears to be a Codex Desktop session loading / migration issue rather than a project code issue.

What is the expected behavior?

No response

Additional information

No response

[github-actions]

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• codex resume interactive picker hangs/freezes when session files are large; codex resume <id> works fine #25430

Powered by Codex Action

[alyakishevdmitriy-pixel]

I reviewed issue #25430.

My case appears different:

• My session files are relatively small (largest files are approximately 1–2 MB).
• New chats open normally.
• The problem started immediately after a recent update.
• Opening older chats results in:

"memory allocation of 2862678 bytes failed"

• session_index.jsonl is only 1974 bytes and contains 14 entries.
• The issue does not appear to be caused by unusually large session files.

This may be a separate regression affecting loading or migration of older sessions after an update.

[alyakishevdmitriy-pixel]

I updated Codex Desktop to Version 26.601.21317, released June 3, 2026.

The issue is still present.

Older chat contents that were visible before the previous update still do not appear. New chats continue to work normally.

This does not seem to be fixed in 26.601.21317.

[alyakishevdmitriy-pixel]

Important clarification:

The old chats are still present in the chat list.

The problem is not that the chats disappeared.

The problem is that chats created before the update no longer display their message contents.

Before the update, the contents of these chats were visible.

After the update:

• old chats appear in the list but their messages are not displayed;
• new chats created after the update work normally and display messages correctly.

This suggests a regression in loading or rendering chat history created by a previous version.

[alyakishevdmitriy-pixel]

Additional observation:

While Codex was running normally, with Chrome open and no actions being performed, Codex became unresponsive and displayed:

"Codex (Not Responding)"

Then an internal crash dialog appeared with:

(code=3221226505, signal=null)

Most recent error:
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace

Chrome was closed at approximately the same time.

This occurred on Version 26.601.21317.

[alyakishevdmitriy-pixel]

Additional information:

I verified that the old session files are not empty and do contain the conversation data.

The JSONL session files still contain messages and metadata from previous chats.

The problem is not data loss.

The issue is that chats created before the update no longer display their contents in the Codex Desktop UI.

Chats created after the update display normally.

This appears to be a session loading/rendering compatibility issue rather than missing or corrupted session files.

[alyakishevdmitriy-pixel]

Additional findings after further investigation:

The old chat sessions do not appear to be lost.

I manually inspected the JSONL session files stored in ~/.codex/sessions and confirmed that they still contain conversation messages and metadata.

Behavior observed:

• Chats created before the update are still listed.
• Their contents are no longer displayed in the Codex Desktop UI.
• New chats created after the update display normally.
• The issue persists after updating to Version 26.601.21317 (June 3, 2026).

This suggests that the session data still exists, but Codex is failing to load or render conversations created by a previous version.

Additionally, Codex occasionally becomes unresponsive and crashes with:

(code=3221226505, signal=null)

while running on Version 26.601.21317.

[alyakishevdmitriy-pixel]

Correction / additional data:

I rechecked the real session file sizes. Some old session files are large:

• one session is about 624 MB
• one session is about 51 MB
• several sessions are around 18–19 MB

So this may be related to loading large legacy session files.

However, new chats work normally, and the issue appeared only after the update.

[alyakishevdmitriy-pixel]

Additional findings after further testing:

I moved the largest session file (~624 MB) out of the ~/.codex/sessions directory for testing.

After removing that session, Codex displayed 13 chats instead of 14, confirming that one session file corresponds to one chat.

However, the issue is still present.

Opening other legacy chats created before the update still causes severe memory usage spikes:

• RAM usage reaches nearly 100% (15.7 GB / 15.8 GB)
• Committed memory grows to approximately 29-46 GB
• Disk usage reaches 100%
• Codex becomes unresponsive and may crash

The issue is therefore not limited to the largest 624 MB session.

Several remaining legacy sessions are significantly smaller (approximately 51 MB, 19 MB, and 18.75 MB), but opening some of them can still reproduce the problem.

In one case, after opening a legacy chat, memory usage increased rapidly and Windows Explorer became unstable. The desktop turned black and Explorer had to be restarted manually.

Additional observations:

• New chats created after the update work normally.
• Legacy session files still contain valid conversation data.
• The chats are still listed, but older chats often fail to display their contents correctly.
• Removing the largest session did not resolve the issue.

This suggests the problem may be related to loading legacy sessions in general, rather than only extremely large session files.

[alyakishevdmitriy-pixel]

Additional update:

After restarting Codex several times, I opened one of the most recent chats.

That chat also no longer displays messages that I had written earlier.

So the issue may not be limited only to older legacy chats. It can also affect recent chats after restarting Codex.

The session files appear to still exist on disk, but the Codex Desktop UI may fail to display the saved message contents after restart.

[alyakishevdmitriy-pixel]

Additional crash information:

I encountered another crash while testing.

This time the crash dialog reported:

(code=3221226505, signal=null)

Most recent error: write EPIPE

Previously I had also seen:

• memory allocation failed
• high memory usage (up to 99% RAM)
• committed memory growth to approximately 29-46 GB

The error message appears to vary, but the crashes continue to occur while interacting with legacy chats.