Windows sandbox initialization fails with helper_unknown_error: setup refresh had errors after upgrading from 0.143.x to 0.144.5

What version of Codex CLI is running?

0.1445

What subscription do you have?

pro

Which model were you using?

_No response_

What platform is your computer?

_No response_

What terminal emulator and version are you using (if applicable)?

_No response_

Codex doctor report

What issue are you seeing?

Environment

• OS: Windows 11 x64
• Codex CLI: 0.144.5
• Installed via:

``bash
npm install -g @openai/codex
``

• Node.js: v24.x

---

Summary

After upgrading from Codex CLI 0.143.x to 0.144.5, Windows sandbox initialization consistently fails.

The same project works correctly with 0.143.x, but fails every time with 0.144.5.

The CLI falls back to read-only mode because the filesystem sandbox cannot be initialized.

---

Error

Windows filesystem sandbox initialization failed

helper_unknown_error:
setup refresh had errors

Sandbox log:

granting write ACE to <project_root>

write ACE grant failed:
SetNamedSecurityInfoW failed: 5

---

Expected behavior

Sandbox initializes successfully and the project is writable.

---

Actual behavior

Sandbox initialization fails.

Codex falls back to read-only mode.

---

Reproduction

1. Install Codex CLI 0.144.5 via npm.
2. Open an existing Git project that previously worked with 0.143.x.
3. Run:

codex

Sandbox initialization fails immediately.

Downgrading to 0.143.x makes the problem disappear without changing the project.

---

Investigation performed

I checked the following:

• Helper starts successfully.
• CodexSandboxUsers ACL entries exist.
• Project root has no DENY ACE.
• No junctions / symbolic links / reparse points exist.
• Git repository is normal.
• The failure occurs during ACL refresh.

The project contains DENY ACEs only under directories managed by the sandbox, such as:

.git
.agents

These appear to be sandbox-related ACL entries rather than manually configured permissions.

---

Additional observations

The sandbox log shows:

granting write ACE ...

SetNamedSecurityInfoW failed: 5

This suggests the failure happens during the ACL refresh step introduced in 0.144.x.

Since the identical project works correctly with 0.143.x, this appears to be a regression in the Windows sandbox implementation rather than a project permission issue.

---

Regression

| Version | Result |
|---------|--------|
| 0.143.x | ✅ Works normally |
| 0.144.5 | ❌ Sandbox initialization fails |

What steps can reproduce the bug?

Environment

• OS: Windows 11 x64
• Codex CLI: 0.144.5
• Installed via:

``bash
npm install -g @openai/codex
``

• Node.js: v24.x

---

Summary

After upgrading from Codex CLI 0.143.x to 0.144.5, Windows sandbox initialization consistently fails.

The same project works correctly with 0.143.x, but fails every time with 0.144.5.

The CLI falls back to read-only mode because the filesystem sandbox cannot be initialized.

---

Error

Windows filesystem sandbox initialization failed

helper_unknown_error:
setup refresh had errors

Sandbox log:

granting write ACE to <project_root>

write ACE grant failed:
SetNamedSecurityInfoW failed: 5

---

Expected behavior

Sandbox initializes successfully and the project is writable.

---

Actual behavior

Sandbox initialization fails.

Codex falls back to read-only mode.

---

Reproduction

1. Install Codex CLI 0.144.5 via npm.
2. Open an existing Git project that previously worked with 0.143.x.
3. Run:

codex

Sandbox initialization fails immediately.

Downgrading to 0.143.x makes the problem disappear without changing the project.

---

Investigation performed

I checked the following:

• Helper starts successfully.
• CodexSandboxUsers ACL entries exist.
• Project root has no DENY ACE.
• No junctions / symbolic links / reparse points exist.
• Git repository is normal.
• The failure occurs during ACL refresh.

The project contains DENY ACEs only under directories managed by the sandbox, such as:

.git
.agents

These appear to be sandbox-related ACL entries rather than manually configured permissions.

---

Additional observations

The sandbox log shows:

granting write ACE ...

SetNamedSecurityInfoW failed: 5

This suggests the failure happens during the ACL refresh step introduced in 0.144.x.

Since the identical project works correctly with 0.143.x, this appears to be a regression in the Windows sandbox implementation rather than a project permission issue.

---

Regression

| Version | Result |
|---------|--------|
| 0.143.x | ✅ Works normally |
| 0.144.5 | ❌ Sandbox initialization fails |

What is the expected behavior?

_No response_

Additional information

_No response_