Is the native Codex/Work Windows sandbox supported when Windows 11 is running inside VirtualBox?

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

26.818.5229.0

What subscription do you have?

Plus

What platform is your computer?

Guest OS: Windows 11 Pro 25H2, build 26200.9168, running inside Oracle VirtualBox. Host OS: Windows 11 Home.

What issue are you seeing?

I would like to confirm whether the native Codex/Work Windows sandbox is officially supported when Windows 11 itself is running as a guest VM inside Oracle VirtualBox.

My environment:

• ChatGPT/Codex app version: 26.818.5229.0
• Guest OS: Windows 11 Pro 25H2, build 26200.9168
• Guest OS is running inside Oracle VirtualBox
• Host OS: Windows 11 Home

The Codex/Work setup repeatedly fails with:

"Windows setup didn't finish"
/
"Unable to verify Windows setup"

Clicking "Try again" starts the Windows setup process, but it eventually returns to the same error.

I have already tried:

• Restarting the guest Windows VM
• Updating ChatGPT through Microsoft Store
• Repairing the ChatGPT app
• Resetting the ChatGPT app
• Re-running the Windows setup multiple times

The sandbox setup appears to partially complete successfully:

• CodexSandboxOffline exists and is enabled
• CodexSandboxOnline exists and is enabled
• BFE and mpssvc services are Running / Automatic
• .codex.sandbox\setup_marker.json exists and is valid
• deny_read_acl_state.json is not corrupted
• setup logs report "errors=[]" and "setup binary completed"

However, the logs repeatedly contain:

hide users: failed to hide current user profile dir (C:\Users\Default): SetFileAttributesW failed for C:\Users\Default: 5 (Access is denied.)

I have not modified the ACLs or permissions of C:\Users\Default because it is a Windows system directory.

My main question is:

Is the native Codex/Work Windows sandbox officially supported when Windows 11 is running inside VirtualBox?

If VirtualBox guests are supported, is the C:\Users\Default "Access is denied" message a known issue, and is there a recommended safe workaround?

If VirtualBox guests are not currently supported, please confirm this so I know whether the setup failure is expected in this environment.

I can provide the full sandbox logs and screenshots if needed.

What steps can reproduce the bug?

Feedback ID: no-active-thread-01a032f0-9e80-7eb1-b1b0-ecc295ebda61

What is the expected behavior?

No response

Additional information

No response

Start by reviewing the Windows sandbox setup logs, especially the hide-users failure for C:\Users\Default, alongside setup_marker.json and deny_read_acl_state.json. Check the repository's Windows sandbox entry points and existing VirtualBox-related tests or documentation, if present. Done means establishing whether VirtualBox guests are supported and documenting or reproducing the cause of the setup failure.