Infinite configure Sandbox agent loop

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

26.515.10909

What subscription do you have?

Plus

What platform is your computer?

Microsoft Windows NT 10.0.26100.0 x64 (Windows 11 Pro)

What issue are you seeing?

So, after the latest update of Codex App it started asking me to configure agent Sandbox and the problem is: every time I click set up it succeeds... but after a few seconds it asls me to do it again and again and again.. I work on a local drive.

sandbox.log
setup_marker.json Here are the logs

What steps can reproduce the bug?

Open codex App
Click on setup Agent sandbox.
It actually succeeds
And than it asks you to do it again and again and again...

What is the expected behavior?

The Codex App always will tell you that it configured agent sandbox successfully but then it will ask you to click set it up again. And There it is... The infinite loop has started...

Additional information

Here are the additional logs that might help you solve this issue:

sandbox.log
setup_marker.json

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

Sandbox setup infinite loop on Windows 11 Home: SetNamedSecurityInfoW fails (error 87) on Google Drive (FAT32) trusted projects + frontend/backend version skew (26.515 vs 26.513) #23108

Powered by Codex Action

You can still run Codex via PowerShell and ask Codex to fix the problem form there.

Codex Desktop was stuck at "Set up Agent sandbox to continue" for all projects.

Root cause appears to be a version mismatch:

Installed Microsoft Store Codex package included resources/codex.exe 0.131.0-alpha.9
Desktop actually launched user-local bin/codex.exe 0.126.0-alpha.8 from:
C:\Users\calle\AppData\Local\OpenAI\Codex\bin

The Windows sandbox itself worked from CLI:
codex sandbox windows cmd.exe /c "chcp 65001 > nul && dir /b"

After replacing the stale user-local bin files with the newer files from the installed Desktop package resources folder, Desktop was able to continue.

Hey! Noticed you are dealing with agent loops/token bleeding here.

I was facing the exact same issue with infinite reasoning loops burning API credits, so I built a lightweight algorithmic handbrake in Python to stop it.

It audits the execution and automatically freezes the agent if it hits the same error 3 times in a row. It might save you some headaches and API costs while you debug the core issue.

You can drop it in your workflow: https://github.com/gedeon1972-svg/loop-guardian-skill

Hope it helps you save some tokens! Let me know if it works for your use cas

I’m reporting a reproduced Windows Codex App sandbox setup/update loop that appears closely related to this issue.

Summary

Codex App repeatedly shows the banner/error:

Unable to update Agent Sandbox / Retry update to continue

However, the Windows sandbox setup log indicates that the sandbox setup itself completed successfully.

Environment

OS: Windows 10, 10.0.19045.x
Codex CLI observed version before reset: v0.139.0
Project directory was on a local drive: D:\Java-p\developer-workbench
Codex CLI could start normally in the project directory.
Codex App continued to show the Agent Sandbox update failure.

Relevant symptoms

Clicking retry/update in Codex App did not clear the Agent Sandbox error.
Renaming/resetting only these directories did not fix it:
- %USERPROFILE%\.codex\.sandbox
- %USERPROFILE%\.codex\.sandbox-bin
- %USERPROFILE%\.codex\.tmp
- %USERPROFILE%\.codex\tmp
Codex recreated .sandbox and .sandbox-bin, but .sandbox-bin was empty.
Sandbox log showed successful setup, despite the UI still reporting failure.
A later App runtime crash also appeared with:
- code=3221225477
- Failed to create shell snapshot for powershell: Shell snapshot not supported yet for PowerShell
Full uninstall/reinstall alone did not fix it, because user-level %USERPROFILE%\.codex state remained.
Deleting all Codex user-level residual files and reinstalling resolved the issue.

Sandbox log excerpt

[2026-06-12T06:41:50.980484400+00:00] ensuring sandbox users offline=CodexSandboxOffline online=CodexSandboxOnline
[2026-06-12T06:41:51.234845100+00:00] firewall rule configured name=codex_sandbox_offline_block_loopback_udp protocol=17 RemoteAddresses=127.0.0.0/8,::/127 RemotePorts=* LocalUserAuthorizedList=...
[2026-06-12T06:41:51.440113900+00:00] firewall rule configured name=codex_sandbox_offline_block_loopback_tcp protocol=6 RemoteAddresses=127.0.0.0/8,::/127 RemotePorts=* LocalUserAuthorizedList=...
[2026-06-12T06:41:51.664394100+00:00] firewall rule configured name=codex_sandbox_offline_block_loopback_tcp protocol=6 RemoteAddresses=127.0.0.0/8,::/127 RemotePorts=1-65535 LocalUserAuthorizedList=...
[2026-06-12T06:41:51.862318300+00:00] firewall rule configured name=codex_sandbox_offline_block_outbound protocol=256 RemoteAddresses=0.0.0.0-126.255.255.255,128.0.0.0-255.255.255.255,::,::2-ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff RemotePorts=* LocalUserAuthorizedList=...
[2026-06-12T06:41:51.876066100+00:00] WFP setup succeeded for CodexSandboxOffline with 12 installed filters
[2026-06-12 14:41:52.827 codex-windows-sandbox-setup.exe] setup binary completed
[2026-06-12T06:41:52.846994100+00:00] read-acl-only mode: applying read ACLs
[2026-06-12T06:41:52.852315800+00:00] read ACL run completed

setup_marker.json

{
  "version": 5,
  "offline_username": "CodexSandboxOffline",
  "online_username": "CodexSandboxOnline",
  "created_at": "2026-06-12T06:41:52.827710+00:00",
  "proxy_ports": [],
  "allow_local_binding": false,
  "read_roots": [],
  "write_roots": []
}

Result / workaround

The issue was resolved only after deleting all Codex user-level residual files under %USERPROFILE%\.codex and then reinstalling Codex. This suggests the App may be stuck on corrupted/stale user-level sandbox/app state even though the sandbox setup binary reports success.

Suggested improvement

Please consider adding a UI action like “Reset local Codex state / Reset Agent Sandbox state” that safely clears stale sandbox/app state without requiring users to manually delete %USERPROFILE%\.codex and lose sessions/configuration.

The newer Windows reproduction makes this look less like a one-off installer failure and more like a missing failure-state contract around sandbox setup.

A useful diagnostic would be to persist one setup attempt record with:

sandbox version before/after
update stage reached
failure fingerprint
whether anything changed since the prior attempt
explicit retry_allowed and halt_reason

If the fingerprint and environment state are unchanged, Retry should stop re-running the same path and surface the captured record. That would also make reports from different Windows machines much easier to compare.

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Infinite configure Sandbox agent loop #23137

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

What subscription do you have?

What platform is your computer?

What issue are you seeing?

What steps can reproduce the bug?

What is the expected behavior?

Additional information

Summary

Environment

Relevant symptoms

Sandbox log excerpt

setup_marker.json

Result / workaround

Suggested improvement

Metadata

Assignees

Labels

Type

Projects

Milestone

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Development

Infinite configure Sandbox agent loop #23137

Description

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

What subscription do you have?

What platform is your computer?

What issue are you seeing?

What steps can reproduce the bug?

What is the expected behavior?

Additional information

Activity

github-actions commented on May 17, 2026

callejoab commented on May 18, 2026

callejoab commented on May 18, 2026

gedeon1972-svg commented on Jun 3, 2026

Keesan12 commented on Jun 5, 2026

kllin8154-arch commented on Jun 12, 2026

Summary

Environment

Relevant symptoms

Sandbox log excerpt

setup_marker.json

Result / workaround

Suggested improvement

Keesan12 commented on Jul 16, 2026

Metadata

Metadata

Assignees

Labels

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Projects

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Development

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