codex - 💡(How to fix) Fix Desktop Preferences can get stuck showing "unable to save" after configVersionConflict on sequential config writes [1 participants]

What issue are you seeing?

Codex Desktop Preferences can get stuck showing an "unable to save" error when changing settings that write to config.toml, even after restarting the app. The underlying app-server error in the Desktop logs is configVersionConflict from config/value/write.

In the observed case, one Preferences write succeeded and updated config.toml, but follow-up writes from the same UI flow failed because they used a stale config version.

What steps can reproduce the bug?

Observed on Windows with Codex Desktop.

1. Open Codex Desktop Preferences.
2. Change settings that touch $CODEX_HOME/config.toml, such as approval/sandbox preferences.
3. Observe that the app shows "unable to save".
4. Inspect config.toml and Desktop logs.

A successful first write was visible in config.toml; for example, Preferences added:

sandbox_mode = "workspace-write"

Immediately after that, subsequent config/value/write requests failed with configVersionConflict.

Restarting Codex Desktop did not clear the user-visible inability to change those settings.

What is the expected behavior?

Preferences should save the selected config values without surfacing an error.

If multiple config values are written as part of one UI interaction, Desktop should either:

• use config/batch/write, or
• re-read the latest config version and retry when a configVersionConflict occurs, or
• otherwise serialize writes so later writes use the updated config version from the previous successful write.

What is the actual behavior?

The first config/value/write can succeed, then later writes fail with:

config_write_error_code=configVersionConflict
Configuration was modified since last read. Fetch latest version and retry.

The UI reports "unable to save" even though the config file may have been partially updated.

Logs

From Codex Desktop logs, redacted for local paths:

2026-04-30T22:35:39.668Z info [AppServerConnection] response_routed ... errorCode=null ... method=config/value/write ...
2026-04-30T22:35:39.673Z info [AppServerConnection] response_routed ... errorCode=null ... method=config/read ...
2026-04-30T22:35:41.600Z info [AppServerConnection] response_routed ... errorCode=-32600 ... method=config/value/write ...
2026-04-30T22:35:41.603Z error [electron-message-handler] Request failed ... error={"code":-32600,"data":{"config_write_error_code":"configVersionConflict"},"message":"Configuration was modified since last read. Fetch latest version and retry."} ... method=config/value/write ...
2026-04-30T22:35:43.624Z info [AppServerConnection] response_routed ... errorCode=-32600 ... method=config/value/write ...
2026-04-30T22:35:43.627Z error [electron-message-handler] Request failed ... error={"code":-32600,"data":{"config_write_error_code":"configVersionConflict"},"message":"Configuration was modified since last read. Fetch latest version and retry."} ... method=config/value/write ...

Earlier attempts showed the same failure pattern:

2026-04-30T22:19:42.395Z error [electron-message-handler] Request failed ... error={"code":-32600,"data":{"config_write_error_code":"configVersionConflict"},"message":"Configuration was modified since last read. Fetch latest version and retry."} ... method=config/value/write ...
2026-04-30T22:19:44.159Z error [electron-message-handler] Request failed ... error={"code":-32600,"data":{"config_write_error_code":"configVersionConflict"},"message":"Configuration was modified since last read. Fetch latest version and retry."} ... method=config/value/write ...

Environment

• Codex Desktop on Windows
• App package path showed OpenAI.Codex_26.429.2026.0_x64__...
• Desktop log client version also showed 26.429.20946
• $CODEX_HOME/config.toml parsed successfully as TOML before and after the Preferences write

Additional context

This looks related in shape to #15310's proposed fix option of persisting sandbox preference via config/batch/write, but this issue is specifically about Desktop Preferences issuing sequential config/value/write calls and not recovering from configVersionConflict.

Manual edits to config.toml work as a temporary workaround, but Preferences still reports "unable to save" for these settings.